I think there are a few problems:
Problem #1: Bad coaching. Mo Cheeks is great at taking a scrappy, undertalented team and getting them to play hard every game. Mo Cheeks is NOT great at teaching Xs and Os. Right now, we need somebody who can teach these players how to play on both ends of the court. Cheeks hasn't shown the ability to do much more than tell a team to create turnovers and run.
Problem #2: Bad bench. Not much Stefanski could do on this front. He had to unload everything to get Brand. With no exceptions or anything of that sort, there was no way to get a solid bench player. Still, you can't blame everything on Cheeks when there's about 6 guys that I actually want to see getting any kind of PT (Speights, Brand, Young, Iggy, Miller, Williams).
Problem #3: Lack of PG Play. Andre Miller has seemingly taken a huge step back. He's not finding open guys, he looks like he has no clue how to run a pick and roll (seriously, Willie Green runs it better than him by far), he seems to have no sense of a double team, and he can't guard anybody on defense. This may be a product of not really having any noticeable offensive plays, but really, it just looks like the last year+ have went to his head and he wants to be a shoot-first PG, which he clearly is not. We don't have a PG on the bench.
So, how do we solve this? Well, problem #1 just requires a fire and hire. Problem #2 requires an offseason with all the exceptions available along with Andre Miller in a possible S+T and maybe a lucky 2nd round pick. Problem #3 requires maybe a signing AND a first round draft pick, which could be pretty high at the rate we're going. The thing with Problem #3 is that there's really only 3 PGs in this draft that stand out IMO (Jennings, Curry, Calathes) and we may not be drafting high enough to get any of them. If we don't get any of them, the PG market pretty much consists of like...Ramon Sessions and Mike Bibby? Unless we can use Miller in a S+T (or in an expiring for longterm with a team this year), that looks like it. In any event, this team is at least a year away.