So, Shamus Young wrote this post about character customisation in Jade Empire, and my response got a teensy weensy bit out of hand...
I loved the Open Palm / Closed Fist philosophies, re: actual personality development. Except for the couple of cases where you had to be straight, mindless, chaotic evil to avoid Open Palm points. Closed Fist actually makes sense, it's harsh but fair.
I disliked that you really needed all three stats. Health/Chi were pretty interchangeable and Focus let you use weapons, which speed the fights up to a bearable point. Basically, you couldn't be a "warrior" or a "sorceror" or a "ninja" - you were always a jack of all trades. I love to specialise.
I also disliked that there were so many styles and you had to put points in just to make a lot of them worth using. My first toon, I spread my points around a lot and had a tricky time in the midgame. They could have fixed this to a large extent by making all the weapon/support/etc styles use one pool of points each.
I really hated the poor descriptions on the abilities. Storm Dragon stuns, it doesn't do damage over time at all. It stuns for longer than Paralyzing Palm. Misleading text like that is a slap in the face, it honestly decreased my enjoyment of the game.
LoTRO customises via traits. Particularly the choice of Legendary trait can be fundamental, or so I hear. WoW of course has talent builds. Oblivion is so back to front it makes my head spin... although it has the unique quality that min/maxing is sometimes HARDER than normal play. Killing Daedra with untrained fists and arrows is tricky.
What I dislike, especially about D&D based games, is how hard it is to identify successful builds. It seems elitist, a kind of metagame that gives an unstoppable advantage to those willing to actually run the numbers. Google 'DDO Batman' to see the full horror of a Rogue 2, Paladin 2, Warrior 6. While I respect Grenfell a great deal, the developers really messed up.
WoW, for me, strikes a good balance between premade subclasses (talent trees) while still allowing meaningful customisation. You can - generally - just look at the talent trees, read the text and come out with something 80% as good as an optimised build. Each plays differently and requires different equipment choices to optimise (the Warlock has to be the prime example).
The most successful customisations allow a revolution instead of an evolution of gameplay. I would have been happier if they'd removed the style and attribute points from Jade Empire entirely, and had instead focused on genuinely differentiating the styles. Thousand Cuts was a big disappointment.
edit: I'm completely onboard with Lee from the OP who hates critical choices during character development. I want to be able to respec *everything*, goddarnit. Yes, even my class. I have 4-5 L60+ WoW chars and levelling another is not an attractive prospect, even though I would love to see the endgame with that char (my warlock is 43).
DDO was by far the worst for this. There were so many critical points in that system that one misplace stat point during character creation could have a massive impact on your future performance. The developers actually considered rerolling a part of the game. You couldn't even create one of the really good characters (with extra stats) without completing 80-90% of the game content. The redeeming 'feature' was that you could hit max level in a month without even trying. Still, you'd be running the same dungeons again, and again, and again.
edit: Up to 12 80s and a 77 now. I've become more casual with the raiding and the DDO model is starting to appeal much more, particularly in reference to Kingdom of Loathing, where you gain an itsy bitsy bit every 'reroll'. I very much like the KoL model.