Celebrim's First Law of Roleplaying is, "Thou shalt not be good at everything."
Character optimization breaks the first law directly by allowing builds that are good at everything, or indirectly, by allowing a player to be so good at one thing - say swinging a hammer - that every problem can be treated like a special case of hitting a nail. An optimized fighter that can slay any monster in a single round is an example of breaking the first law.
However, since the first law is also superior to the rules of any particular system, any rules system that allows you to be good at everything is also a bad system (at least in that respect, it might be worth salvaging though). In fact, arguably the entire point of any role playing system is to obey the first law. Stock 3.X played with most of the supplements and without modification fails this critical test.
"...combat brute, pounce, and with a valorous weapon, haste and a brilliant energy weapon or just wraithstrike cast upon"
I'd note that none of the above mentioned abilties or items exist in my game.
"add shock trooper, leap attack, frenzied berserker and a belt of battle!!!"
None of those either.
There are comparitively few ways to break melee in the core rules. If you expand on the core rules by making available poorly play tested supplements pushed out primarily with the intention of pocketing your money and with little attention to its actual impact on your game, whether those supplements are from a WotC or a third party, then on your own head be it. In my opinion, it falls on the DM to ensure that the game is balanced. This requires the DM to not allow every option that someone has published in to the game blindly and requires the DM to set out what is available and what isn't. I think it is a mistake for the DM to leave it up to a social contract an understanding of what is 'fair' to build. The temptation to shine, to succeed, and to at the least not die is too strong and too perfectly understandable to ask of the player to sit in a room full of goodies and refrain from partaking of them. Power will creep into your game in the long haul as one player pushes the limits, and the rest of the players - feeling deprived of spotlight - begin pushing the limits as well.
One example of that very tension will be a refrain that's either already in this thread, or would be shortly. Some one is sure to say (or have said, I didn't look): "Yeah, but there are far more broken builds than that." or "The most broken thing in core is a single classed wizard" or "You just think that fighters shouldn't get good stuff" or "As long as there are CoDzillas, then I need to do this."
By the time your game gets to that point, it's already got big problems. Sure, you can sorta get by skirting the edge of the first law by a table agreement that lets everyone be good at everything ("If everyone is special, the no one is.") but in the long run even that doesn't work out.