AbdulAlhazred
Legend
This, a dozen times over. I neither want nor need the "holy trinity" in DDN in order for my party to be successful. yes, I imagine a group of rogues would have the game tuned differently for them than a group of paladins or wizards, but that's the POINT. D&D must be able to adjust to each group, each group must not need to adjust to D&D. The goals, the methods, the adventures will be totally different for a group of thieving scoundrels than a group of heavily armored knights. That's the point. Without that kind of flexibility in gaming, D&D is no more than an TTMMO.
I guess I'm not sure how the existing game design in 4e fails to meet that. If you build a party full of rogues then you had better approach challenges in a different way than if you built a party full of heavily armored knights. You COULD work into either group a leader, and said leader will have some healing, but that isn't going to transform those groups into clones of each other by a long shot.
I think, as in all editions, there's generally a 'default' party because generally players don't get so focused on a specific type of game. They just come together to play 'some D&D', not to play a 'rogue campaign' or whatever. So typically you end up with one of each sort of PC and those sorts of parties in 4e are pretty interchangeable. They'll use slightly different tactics is all.
OTOH if you DO make an all-rogue party, its going to play a lot different, in every edition. Frankly such a party is probably going to be pretty non-viable in AD&D, except for a VERY niche type of investigative play. In 3.x such a party will do better at lower levels, but they'll still have problems with harder adventures. Again you would play a certain type of game, but not so extreme. In 4e you could make it through probably most normal adventures if you were really careful, but using unusual tactics. In ALL of them you'd be struggling to stay alive with insufficient healing.