I believe there is a place for both type of cons - the *real* comic cons and the "fan-cons". Personally, if I'm taking my kid, he's going to have a better time at the "fan-con", than sitting around while his dad rummages through yet another long box.
I don't mind the cosplayers too much at the big shows, as it's what one expects now. However, it's gotten steadily worse over time. Personally, I think it could be limited, if done correctly. Perhaps, if you want inside as a cosplayer, you have to register as such and a panel of judges gets to decide who is the best - just like a costume contest. Only a certain amount are allowed through at any time (which would prevent 62 Batmen and/or Harleys) with alternates who could rotate out during. Give the winners a discount/free admission, BUT they must follow certain rules, no blocking tables/aisles, or heck... even helping promote some of the dealers/artists. If the other freaks want to L.A.R.P., let them do it in the lobby and not in the hall.
Cut out the carp not related to the industry, (was anyone at WWChicago when they brought in the Governor at the time to sign autographs for like $50? ) this could be easily fixed by pre-screening applicants and rejecting those that want to sell fake weapons, or hippie-stuff.
I personally prefer the old-school "gentleman/lady" conventions. There are several reasons, but the two that stand out the most are mutual respect among attendees and the lack of noise. Too much noise is distracting and makes it hard for me to focus and I end up getting in a hurry rifling through stuff. Also, not having someone try to shove you when you're digging is nice. Actually being able to talk to dealers without having to shout, what a concept. Not having dealers distracted that someone is going to snatch something if they don't have 16 eyes watching everything is nice too.
There should be no issue telling someone they cannot bring their cosplay gear to a "gentleman/lady" con. They have their place elsewhere. I see it like this, one can go to a whiskey or wine tasting, or to a strip club, they both revolve around alcohol, but I don't wanna hear about "Coming to the main stage - Harley!" at the wine tasting.