I realize that admitting everyone to Eucharist because the Eucharist is special is counterintuitive. We ordinarily believe that something is special when only some are allowed to participate in or partake of it, when it is reserved for some elite or other. In fact, one of the ways we define specialness in our world (and let's be clear it is a worldly definition) is by limiting access in this way. If something is available to everyone then, by definition, it ceases to be special and becomes common. When we realize that this is the deeply engrained way we think and run our world, we also begin to understand how radically Christianity undercuts our normal worldview. It says instead that the most precious realities we know are meant for everyone, not for an elite few. It says that in fact, in a world where things are measured according to whether or not they are common or a limited edition with limited access, and where a person's value is measured in part by how much access they can afford or otherwise earn or merit, what is truly rare is something where access (and thus, the love of the community in Christ) is available to all without price. Wasn't this part of the meaning of the Incarnation? Wasn't it what Jesus himself modeled for us --- even when he was badly treated or the disciples tried to fend people off and prevented them from touching him? Isn't it the reason Jesus' life and death tore asunder the veil between the sacred and profane, heaven and earth? Isn't it at the heart of our theologies of grace and redemption?
In fact, I believe that this kind of access to the Sacrament is a piece of valuing it appropriately. I believe that allowing such access must be complemented by treating the Eucharist with as much reverence as we can at all times (something we can certainly improve on in most parishes), by making sure our ministers act out of this reverence and model it for others, and so forth, but I believe both of these elements are part of treating the Sacrament as the most truly Sacred reality we have ---along with the Word of God, the other Sacraments and Church herself. Similarly, I believe we each demonstrate our sense of being both called and chosen not by excluding others but by inviting them to participate in the Communion which enlivens and empowers us. More, we do this because in this way we proclaim the Sacrament a gift we can never merit ourselves and therefore, can never exclude others from if they sincerely wish to participate.
As far as admitting public sinners to the Eucharist I believe part of the problem has been separating our universal identities as sinners from our ability to receive the Eucharist. Our focus instead has been, perhaps, too much on "being in the state of grace." If we were to make it clear that we welcome public sinners to join all the rest of us sinners in receiving the gift which empowers repentance (as , by the way, our prayers before Communion proclaim when they say, "Lord, I am not worthy. . ."), the Eucharist could no longer be used by those in good standing to brand others.
While I believe we ought to treat the Eucharist with the utmost reverence, I do not believe that allowing sinners to approach the Lord's table constitutes sacrilege unless they are approaching in order to consciously thumb their nose at the Faith we hold. And in such a case the injury is being done to themselves, not to Jesus. God risks in loving us. We take the same risk in loving others in this way. As I understand it, allowing sinners to approach the table to foster reconciliation and build unity is the reason we were gifted with Eucharist. Too, I am reminded that in the NT it is Jesus' holiness which is "contagious" and makes holy, not the other way around. Jesus is never made unclean by consorting with sinners, touching the sick or dying, breaking kashrut, and so forth.
What about eating and drinking unworthily (1 Cor 11), especially since we universally proclaim our unworthiness before Communion? It's an important question of course, but what did Paul mean by that? What was the situation in Corinth? Remember that everyone including the socially well-off were bringing food and drink to the meal. The poor brought less, the rich more and there were inequalities and divisions in the actual meal. Also Paul had been trying to hammer home the notion that in Christ there are no distinctions; there may be different gifts but they are from the same Spirit in the same Body. The Corinthians had bought instead into the notion that some gifts were special, others less so, some were called to a greater spiritual life or holiness than others who were supposedly called to or gifted with less. Unfortunately those with greater social advantages mistook these for spiritual gifts as well. Their celebration of the Eucharist reflected all of these distortions of the Gospel. Any interpretation of what Paul means by eating and drinking unworthily must bear this in mind.
Thus, I think Paul's reference to eating and drinking unworthily actually involved his judgment on elitism and the practice of giving a greater share in the Eucharistic meal to some than that given to the poor and those considered "less spiritually gifted". At the same time then, neither do I think he meant approaching the Eucharist as though we ARE worthy, as though we DO merit such a great gift, as though we believe reception indicates our relationship with God is "just fine thank you very much" and in fact, is better than our neighbor's, is ever acceptable! Those who receive a gift no one can merit can only do so unworthily if they ignore, forget, or otherwise refuse to claim their identity as sinners who in no sense can EVER merit this great gift. Personally I think this is a far bigger and more insidious problem with our Eucharistic praxis today. Paul was speaking of those who disdain the meaning of the Sacrament in an elitist and divisive way. This was what Paul might have considered "public sin" in his communities.
Similarly since Paul was concerned with a Church some of whom had denied Jesus' resurrection they may have doubted they receive Christ's very Self in this Sacrament. Today people may receive because they are making some political or similar point with their reception. In other words, they are using the Sacrament for their own agenda, not making themselves open to God's! Let me also be clear about one thing though. If a person believes in her heart of hearts that receiving is wrong, then it is wrong and receiving would be a sin, potentially a very grave sin. The sin here is that the person acts against conscience; it would remain wrong even if she were really in the state of grace otherwise.
When we are dealing with such a great gift as the Eucharist we are going to run into problems (or at least tensions) in regulating its celebration and reception. I personally believe that the greater problems fall on the side of self-righteousness or complacency. I believe it is more pernicious and problematical to allow folks to believe they actually DO merit Eucharist in some sense because they are "in the state of grace" or can make a fidelity oath than it is to cultivate the sense of our prayer, "O Lord I am not worthy. . ." and open Communion to those who are thought to be (or even those who really are) public sinners.
The idea, of course, is to let everyone have a sense that what we do here is, to some extent, different than what we do elsewhere, that it is weighty and, for instance, requires gestures we use nowhere else, gestures, etc that are done thoughtfully and with reverence. If we can do this we can provide a context which opens Eucharist to public sinners (and to us less-public sinners!) which can empower conversion. Especially we can make it clear that this Sacrament is special precisely because it is meant for every person, not for an elite. This is the countercultural or "anti-world" lesson we really need to teach in our Christian praxis and worship.
Finally, let me answer your questions about heresy, etc. What I have said here about admitting public sinners is not heretical. It pertains to discipline, not to doctrine or dogma. Further, I have fully honored and supported the Church's theology of the Eucharist in what I have written here. I argue as I do BECAUSE I believe fully in the Real Presence of Christ in the Eucharist, as well as in the proclaimed Word, assembly, and priest. As for my hermitage the Eucharist is reserved here for only two reasons: 1) for my own needs because of the demands of eremitical solitude, and 2) because occasionally someone in the immediate neighborhood (part of this parish) may need someone to bring them Eucharist if they are ill. If my pastor were to say Mass here, especially on a special day or feast, it is possible a couple of others could also attend (though not while on lockdown!), but my own celebrations of Communion here are private. Even my diocesan delegates do not ordinarily receive Communion with me here. I assume my Bishop is aware of the contents of my Rule, that he occasionally reads this blog, and I know that I am appropriately trusted to be duly reverent of and responsible for the (reservation of) the Eucharist entrusted to me. More than that I cannot say.