Visually you somewhat get a hierarchy, but yeah. Honestly I'd like to see a blend of sub-factions myself and visually distinct territories. In Fallout 3 I didn't mind the Raiders so much as their presentation of what appeared to be aggressive punks that are all apparently permanently on some paranoia-induced drugs. Sort of can tolerate it what with the various Vaults in the area that had lead to the "Crazies" developing.
What I'd like to see is clear and distinct weapons, armors, heck even graffiti and tattoos separating one group from another. Have it so each gang of Raiders has their own central base, leaders, tactics/equipment and also source of said wares. Sure, it may end up where the Raiders are still mindless killers for the most part, but at least you have to adjust to their tactics instead of having most of them use SMGs with a few carrying flamethrowers.
Tactics themselves will not exist though unless they script outside the random generations. Fallout 3 did do quite a bit of interesting "special" encounters that do help develop certain generics a bit more. An example would be... the bomb wastelander, who blew up due to Raiders rigging him into a trap. Or examples such as Slavers chasing after escapees. Things like these develop an enemy group a bit more, but really shouldn't just be a "special" encounter. If you want the Super Mutants to act more intelligent, have them scripted to bait you in the areas that you'll normally encounter them instead of it just being a random thing you walk in on. Or do give them scripted duck-and-cover capabilities. Sure, it may run into some problems, but considering the fact I've already seen NPCs run off to where they consider themselves "Safe" I don't think a cover option isn't that far away.
What DOES make the Super Mutants gain more ground towards their original intimidating forms was one of the previews of New Vegas - Nightkin, specifically. Their return is great and the "melee" form's execution during the video stunned me and actually terrified me. There's nothing like the image of someone blasting away a Super Mutant, the body clearly falling to the ground.... and then the "Real" mutant suddenly popping into your visuals right in front of you to break your teeth and part of your skull. If Obsidian continues this trend of making enemies intimidating due to special tactics and abilities that each has, we'll have a bit more diversity than Hulk-smash angry at everything mutants/raiders/random small children.
Edit: On another note, I think I found what we have to blame for the Super Mutants appearing and acting like they do in Fallout 3: The Xbox "Brotherhood of Steel" game. I recently reread the manual of the copy I own and it describes FEV result in experiments turning aggressive, being insane, and having a degraded intelligence - this being FEV prior to scientists experimenting on it more. Also, the "Super Orc" asthetic apparently spawned in that game too. So shame, Bethesda, for basing their Super Mutants on a game that so many people had already hated D: I find the thing fun still though. Lack of Cattleprod made me sad though.