Dungeons and Dragons Online has an incredibly deep character development system. The game itself isn't all that complex, but when planning characters you may as well be playing EVE. You have to allocate stat points when you roll a character, which is damn easy to mess up when you first start playing. This is not Everquest, where the stats you get from gear will trump any other consideration. You will be feeling the effects of your choices at level 20. You also have to pick one or two feats from a list of dozens, pick out enhancements from an equally huge list as you level, and allocate points to skills.
Unfortunately, the descriptions rarely give you much of an idea of how useful something will be in game. For example, it's hard to know whether "jump" is a good investment of skill points until you know how often you really would want it (I've found exactly one instance so far that lack of jump skill screwed me in, out of dozens), or whether there might be some spell or dead common potion that can boost your jump skill when you do need it (yes and yes).
On top of that, as a friend of mine pointed out last night, the in game feedback often isn't too helpful. He tried to equip spells on a Paladin that had 8 Wisdom. The only feedback he got was "Stat isn't high enough." Umm, what stat exactly? How high does it need to be? An error message along the lines of "Must have at least 12 wisdom to cast level one spells" likely would have been a lot more helpful.
The situation we are left with is that you either have to follow a "flavor-of-the-month" build step by step on the forums, or you guinea-pig several builds until you find one that does what you want it to. There are character planners that can help somewhat, but no character planner can tell you whether an ability or spell is any good for your play-style. You have to take it for a spin.
Added to all of this, the fact that you can mix and match levels of different classes at will means that (A) you can design a character to do almost anything you can think of and (B) your opportunities for gimping yourself are nearly unlimited. I like the depth on the balance. It's a refreshing change of pace from most level based MMOs, where the majority of characters of a given class are nearly identical until at least the mid-levels. However, I have to admit it's not a real pleasure to get some random build up to level 3 and find out I screwed up and have to re-roll . . .for the second time.