Ok , so I'm going into a 3.5-based D&D-PBP game (Paths to Glory) and Enkh.(The DM) mentioned that 3.5 did away with the Amb.-requirement for TWF.
Munchkin-wise , I'm really happy with this , since it leaves me another feat to choose from.

As far as Real Life(tm) is concerned , however.....
A few facts first:
-I have an innate talent for ambidexterity ; It's kinda family-trait.
-I have learned to fence the Rapier&Main-Gauche
-I know I always had the upper hand on those with no talent for Amb.(If you can't even write your own name left-handed(in the case of right-handedness , ofcourse...) there's not much gain in learning this way of fencing)

Now I ask you : Does this 3.5-erratum make sense?
It doesn't to me...
But I might be overlooking something.

It makes sense from a rules standpoint. Ambidex really did nothing for anything other than two weapon fighting, and with the restructuring of weapons to the newer weapon sizing system, it made sense to streamline ambidex.

This is at least the way I see it.

I have grandfathered this in my game to keep the 3.0 way.

What about the advantages of ambidexterity in terms of being able to fight with either hand with no penalty? Or being able to draw two weapons at the same time as part of a move?

Plus, some people are just ambidexterious and never learn to fight with two weapon. . .what if you want to emulate that?

Again, me and my players we make characters to fit visions of characters and the rules are generally an after-thought.

If you really want to return Ambidexterity to the game, I suggest using the rules from Arcana Evolved. There, the Two-weapon Fighting feat reduces the penalty for TWF by 4 for both attacks (instead of 2 and 6), so someone fighting with a light off-hand weapon and having TWF gets -0/-4 instead of -2/-2. TWF also doesn't require any Dex. Ambidexterity is a Talent, which means it can only be taken at first level and you only get one (with certain exceptions), requires Dex 15, and reduces off-hand penalties by 4. So someone with both can use an off-hand light weapon without any penalty at all. There's also a third feat, Massive Two-Weapon Fighting (Prereq: TWF, Str 17, BAB+7) that lets you treat any off-hand weapon as light.

All in all, this makes basic TWF slightly stronger than in 3.5e (no prereq, and 0/-4 is better than -2/-2 since the main attack is usually stronger than the off-hand attack), and allows for a feat to make it even better.

The downside is that the equivalent of Improved TWF requires BAB +9 rather than +6, and there's no Greater TWF.

I like the AE system much better as well...  Two-weapon fighting isn't really a viable choice in vanilla 3.5 when you get a -2 to all your attacks for 1 extra strike per round, at the cost of 2 feats.

In vanilla 3.5, it's one feat (since ambidex is folded into twf). Two feats is 3.0.

And if you're willing to invest more feats, it's more than one extra attack.

My players tend to pick that fighting style a lot, so unless they're complete morons, I would tend to think that it's a purty good option as is.

One of the reasons for learning that style of combat is that it looks good. Seriously, it's the best way to wench around. Hiding behind a shield looks cowardly, wielding one large two-handed weapon looks brutish. But with one blade in each hand, you look dangerous and chicks dig that, even if it's not the best fighting style ever for more practical purposes.

All offense, but in a graceful way, one that shows adroitness and panache. Fighting like a tiger, like a whirlwind, attacking two foes at the same time... The ultimate swashbuckler!

It's also the best option for people who are nimble enough to not terribly need a shield, yet aren't strong enough to kill an enemy with just one blow. Then it's better to maximize the amount of attacks you can do. If you wield yoru weapons with finesse, rather than brute strength, you can manage to score more hits and bleed your enemy to death rather than slay him in one powerful blow.

This is also especially when your weapons relies less on strength and more on something else to damage your foes. Sneak attacks in vital organs, poisoned or enchanted weapons, or better yet, sneak attacks with enchanted and poisoned weapons. Then causing a deep wound is irrelevant, causing a lot of wounds, even superficial ones, is better.

I prefer the 3.5 way (one feat).  Really, I don't care whether it's more realistic or not.  Two feats is too high of a cost, rules wise.
 
When the system, as a whole, is so large-grain, I can't see this as a big deal.