I see where you're coming from, but I'm not entirely sure if that's the best approach.
Let's take Dragon Age as an example. In that game, the equivalent to AC actually matters, and having a tank doesn't keep you from using him/her to kill things - neither do the monsters ignore him/her in favor of squishier targets. A Rogue becomes absolutely essential because the game is completely RIDDLED with traps and locked treasure chests (my main in that game is a rogue). The mage becomes your bag of tricks: you can use him to buff, heal, or kill things in an area (yes, melee types can attack in an area too, but their range is shorter, they deal less damage and have little means of debuffing multiple enemies). They are also, however, made of wet tissue paper (unless optimized for tanking) and you simply can't get around that no matter what you do.
Dragon Age is, unfortunately, very much two-dimensional to use as a measuring stick. That's because it's a computer game, and by definition a computer game must have as many of the possible outcomes coded. D&D doesn't work like that. The Wizards don't have an option of one quickbar to solve their problems - they have a dozen of those. The Fighters, on the other hand, have auto-attack... maybe grapple and trip. And they won't be automatically good at that.
Terrible analogy. Dragon Age is plagued by casters being dramatically overpowered... playing a party of three casters and a Rogue (Leilana as a bow rogue, solely for traps/chests, scouting, and pulling) is like playing in god mode. One caster drops the Earthquake, the next drops the Blizzard (now nothing can move or act and everything's taking damage) and the last one uses Tempest to make sure everything stays dead. Even the fight you're supposed to lose because it's supposed to be impossible becomes trivial. You can even have your casters tank better than Fighters by taking the class that lets them wear heavy armor and use their magic rating as strength. Dragon Age has exactly the problems of D&D... Rogues are only good for stuff that is specifically made Rogue only (disabling devices and stealth) and casters do everything better, so tanks are just there to look pretty.
JaronK
This was the same way I ran through it. One damage dealer Caster, Two Tank casters (my Main and that healer chick) where one doubles as the healer, and one rogue because only rogues can open locked doors (I used Leliana too).
Everything started with casting the three crowd control spells on any target they could see, then the tanks keeping to the outside so they wouldn't take damage from running in there, and the caster and rogue attempting to pull them out. Needless to say, the rogue never did anything because the Tank Casters just couldn't die, and when they were close to, just one Minor Health potion was needed.
On the last boss, I tried a different party set-up (for various reasons which I wont spoil, some party members become unavailable through the game), the entire party died, except for my Caster Tank main, who just went over to the BBEG and chopped at it with an axe untill it was dead, whenever he was low on health (which took like 5 attacks) he would sip one of the least potions to gain more health.
This was probably more a problem with the Arcane Warrior class making you into the most SAD character ever. When you suddenly use Magic to give you mana, Spellpower, Damage, Which armours you can wear, and hit points weren't decided on stats. You stop worrying about it.
If you want to see a system were the fighters have options that still seem realistic but allows a choice in battle, Runequest is a decent system. The wizards in that game can only cast 1 or 2 spells per day, and will have to rely on mundane things for the rest of the day. That is a system I like way better than 3.5.