Thanks for the detailed explanation on why the deck is so high for this show. I suppose they could conceivably remove the concrete, but obviously, that would be quite an effortful and expensive undertaking.
As for your other comments, I guess it largely comes down to one's personal tolerance/enjoyment level in regard to watching characters behave badly. But in this case, as several people pointed out, I think that's greatly tempered by the fact that Wheeler is written and portrayed as a very funny fellow, very smart (in some ways!), and generally good company -- which is why his friends put up with him (to an extent) despite some horrendous behavior, and also why some audience members (though apparently not you!) enjoy observing him in action.