I suspect not however because you have to CLEAR OUT THE JEFFERSON MEMORIAL and I'm sure there are other points where combat is forced on you and there is no speech option to get out of it.
You're only forced into combat once and that's where you have to kill a radroach during the tutorial. You can skip every quest in the game and proceed straight to the ending if you know where the final "level" is and there are several primary quests you can just work around. The world is more dangerous, though, but a high perception lets you spot enemies you haven't seen on your compass and a high sneak means you can just avoid them.
Also in F2, Speech was not just SUBVERTING THE QUEST, it was a different outcome for the quest, you would still recieve exp and level up just as fast.
Uh speech in the previous games let you either avoid combat or bluff someone into thinking you did whatever it was you were supposed to do. Same thing in this game. You still get experience and stuff but just like in the previous games if you speech your way through everything you'll have less experience and equipment than if you blasted your way through whatever dungeon.
Speech and certain perks (child at heart and lady killer/black widow) make characters give you specific rare items so a speech focused character can essentially pad their low equipment handicap but just like EVERY western RPG where you can bluff your way to victory you won't have all the cool equipment a combat oriented guy would have.