DMC4 was an incomplete game in many terms, but i have to agree with some things Caiden said. Most of your dissappointement is just like, your opinion. I don't really get why some people can dislike so much DMC4 Dante, i don't even remember people saying that kind of thing when the game was released; the main complaint in that aspect was about Nero, everyone disliked Nero at a first glance.
But, btw, i'm not going to type some wall of text here, i think too that DMC4 was an incomplete game and the sad part is that it had the potential to be the one greatest DMC game out there when you look at all the rumors. But gameplay is definetly something that they get right and could even develop from there (even more when we talk about Nero that was pretty "raw" in DMC4 and still holds a cool branch of possibilities), Dante's gameplay is a clear evolution from what DMC3 was, it's not nearly a mess, it's very organized, you just have to take your time to learn because there's a lot of things to get the hang off. When we come to this point, even the first DMC was a much more enjoyable experience once you learned to use Dante's arsenal to its fullest extent and some techs that were boring to learn and incorporate to your playstyle (like sword-cancel and dt-cancel), even the first game had some skill celling to be appreciated in a better way, even if was much less than the subsequent games in terms of execution.
EDIT:
About DMC4 enemies that berto was talking about, i think that they were a large development from DMC3 enemies. I mean, if you look at DMC3, JC (enemy step, in reality) was a core mechanic that was first encouraged and taught to the player in some of the secret missions that later more expert players developed and make it be what it is for DMC players now. But they dit not work the lesser enemies to deal with aerial combat too much (the only one "basic" enemy that is a real pain in the ass when it comes to knock you off the air, and basically only in DMD or Very Hard are the Lusts). DMC4 enemies, even the more basic ones, had attacks to deal with you when you took one of his friends to the air, you feel much more threatened in the air in DMC4 than you did in DMC3 in a lot of cases. The enemies movesets in DMC4 are larger too, kinda revolved to its roots in DMC where even marionettes had a good list of attacks.