Here's the way I look at it, even if it is a little simplistic.
The success of Igor's offense has always been dependent on the play of the point guard and the big men have always been secondary, or even third on the pecking order. Igor has the exact opposite kind of roster he's used to, whether that's for his asst coaching days or his national team days. I would almost guarantee we would see IMMEDIATE dividends if we acquired a point guard with some inherent NBA skill. You can see it coming out of Point Book. Problem there is that he's a natural SG and will never be totally comfortable in that spot.
I'm not saying we'd be an automatic playoff team with an established point guard, but I think we would see a big difference with the product on the court, pretty much with EVERY player.
The offense itself is dependent on something we don't have. Now the problem is adjustments. Igor is learning, as evidenced by his starting lineup changes and the release of Canaan/trade of Chandler. However, he needs to go another step further and change the fundamentals of his offense to fit his personnel. I think it's painfully obvious that he doesn't know how to do that yet. In today's NBA, you can't adapt the personnel to the offense, you have to adapt the offense to the personnel. It's no secret most NBA players from bottom to top are usually pretty one-dimensional.