Haffrung Helleyes said:But there are some basic ideas built into d20 that are hard to get away from, that make it hard to simulate some genres:
1) play is centered around the idea of a 'party'. Much literature is centered around a single heroic individual and his sidekick
2) characters grow significantly in capability over the life of a story in a d20 campaign.
As you note, these aren't really criticisms of D&D. At worst, they are criticisms of RPGs as a whole, for pretty much every game has these elements, probably because, as you say, they make gaming fun and social. A game that purposefully limits the party size to one or two people, or that eliminates character growth, is likely to fail to interest most of the gaming community. Seems to be in the nature of the gaming beast.
Jürgen Hubert said:GURPS allows a customization of characters that is as far as I know simply not available with any of the current variants of d20.
On the other hand, GURPS seems to require that you have something beyond the core rules to make it function. You need to have Transhuman Space, or GURPS Somethingorother (or personal homebrew work of equivalent magnitude) to get much in the wya of coherent flavor from the system. IMHO, Gurps goes so far in trying to be generic that it hamstrings itself.
There's an old saying about being open-minded: the trick is to not be so open-minded that your brains fall out and spill on the sidewalk. This basic precept works for games, too. It is good to be flexible. But if the game is too flexible, it becomes a limp and bland noodle that supports nothing well in and of itself.