In my opinion, The amount of main-eventer isn't a big deal, but the amount of time given to them is. Main Eventers are meant to draw crowds. Everything night someone watches wrestling, its the main event that people want to see. Now you can call me a little bias, but to me, WWE is utilizing their main eventers perfectly.
1. Rey, CM Punk, Big Show, Kane, And Chris Jericho are guys that I call main-eventer/mid-carders, which means they can easily fill either role. Main event or mid-carder match while still appealing to the crowd. If you notice, these guys are barely ever always in the main event, but thats cause they are not always on the world title hunt (where the main event always seems to revolves around the world champ). So about half of the WWE's list of main-eventers aren't "total main eventers" which is good.
2. The concept of multiple shows is great. Although WWE does have a lot of main eventer, thats okay because they have like 60 other wrestlers that aren't and they are getting their air time. NXT focuses on rookies and pro that are more like mid-carders. Superstar features mid-carders. Smackdown is probably more like main-event/mid-carder. and Raw is for the main event. There is balance and everyone can get attention, other then the divas atttention, which is sad.
The only other thing I don't like about having all these main eventers is that they have been winning the tag titles often, like Batista and Cena from a while back. These two men are clearly not a team and didn't need the tag titles to boost their already great career. I don't think main eventers should have tag teams unless they are acting like a mentor for a young star. And I guess WWE is going to have to be careful at some point because from the looks of it, WWE is creating more stars main event status. This isn't bad thing, but could result more main-eventers taking air time.
As for TNA, I don't like how the main eventers are used. It might be due to their limited show and air time, but still.
1. I don't know why the heck they keep using Sting. The guy has a shoulder injury and his matches will be short, so stop using him, and let him heal. Lately, PPV has been disappointed, but thats only because everytime Sting wrestles, its a rip off for the fans, and that only, ruins the PPV, for people. He is a great wrestler, and he should put on a great match, but its hard if he has a injured shoulder!!! Look at it TNA!! The bad thing about TNA is that they tend to rely on their main eventers too much, and they don't open to the idea to take the opportunity to use it to make young stars.
2. Samoa Joe and Anderson are probably the only guys on that list I consider mid-carder/main-eventer. If they want a more balanced roster, they would focus on making stars like that. I think Abyss, Foley, and Flair can help cover that. P.S. (Why is Hogan on the list? He barely wrestles, and he can't actually due to injuires).
3. One of the things I don't like about TNA is that, to me, its the same guys over and over. Its RVD, Styles, Hardy, Sting, and Wolfe and The Band in the main event picture. That takes up like half of the show. I do however, appreciate the time they give guys like the x-divixion and the knock outs, but its like, where the heck is Rhyno, or Shark Boy, and Christopher Daniels. The originals!!! Its all guys the TNA signed recently. If you look at your TNA list, more then half of those guys are guys that TNA signed in the last 3 months, which I feel is a huge middle finger to the originals that deserved to main event more then those guys.
So to me, its not the numbers of main-eventers, but how they are used.