I don't even know where to begin to address how wrong you are. Let's take the character development thing. One of the major themes of season 6 is Tony getting countless opportunities to change (including an actual NDE, which is often a powerful inciting event for personal growth) but basically deciding to take the easy way out and continue to be more or less the same sack of shit that he's been for the past five seasons. It's pessimistic but also meaningful and cautionary. As for the other characters in the show, most of them are middle-aged and set in their ways. Should they all change just because it's the final season? Even then there is plenty of meaningful character development; Vito coming to terms with his homosexuality and trying to get out of the mafia life, Melfi beginning to understand that her therapy may be doing more harm than good, etc. I wonder what character you think should have developed more, but didn't.
The series doesn't even end in a particularly unresolved place. The final scene is unresolved, yes, but there's plenty of closure in the last few episodes and there's enough information provided in the season as a whole that you have a pretty good idea where every character's at by the end.