Honestly, I think the midcard issue is a completely separate beast. It seems to me that people keep placing the blame on things like "too many titles" or "part-timers" when the real issue is that WWE simply does not care about or know who to effectively deal with their midcard.I really do believe that this mentality is indicative of how many in the IWC think. They seem to think that without part-timers WWE would be forced to or be able to focus on the midcard more. I disagree with that assessment.
I also disagree with this mindset, and you are certainly not alone in this, that the title always has to be the top focus or centerpiece of a promotion. It should be more of than not, but occasionally issues do and should bubble up that mean as much, if not more, than the belt. It's not the end of the world to have your title be "an important storyline" even if it's not "the important storyline."
The issue with the midcard is they simply don't treat it correctly. It has nothing to do, at all, with bringing in part-timers or having too many belts. If the part-timers disappeared tomorrow I sincerely believe that the midcard would be in the same pitiful shape it's been in so long as I can remember. Guys like Barrett, Cesaro, Kofi, etc. would be treading water just as badly as they are now.
Now WWE has elevated some acts like Ryback and The Shield. The problem is that they still don't treat those who are still in that midcard realm as if they matter at all. Not everyone is going to make it to that top level, but why not book in such a way that you get some level of separation between guys like Barrett, The Miz, Kofi Kingston, etc.? Those guys pretty much just seem to trade wins and it never really matters. When they get to rub shoulders with the "big boys" they get completely punked.
It is frustrating watching WWE treat talented individuals this way. It's just as frustrating seeing people blame this on interesting acts like Brock Lesnar and The Rock. Like the part-timers or not, I don't really care. Just don't think their absence suddenly makes WWE's midcard a lot more interesting.