Well I suspect my enjoyment of 2772 is probably more than yours, and don't fiind myself having to be apologetic about it in general, however I realize it is a film I can't show to that many (though I have screened it at the AS220 down in Providence.) I think if you are a Tezuka fan and a Phoenix fan, then the film is highly rewarding. But here's where your points about inaccessibility stand out, because without my two stipulations, the film can certainly be seen as a dud, or at least very odd. To be honest, in execution I see it as very close to Tezuka's experimental films. Sometimes he seems willing to sacrifice continuity for a whim and that can be frustrating. On the other hand, he does much the same things in his own manga, it just works better in that context.
All that said, I really do love 2772, but it is with all those caveats in place. Phoenix and Leo are also my two favorite works by Tezuka, so perhaps this isn't surprising.