50 would be insane and would possibly make New Vegas even more broken then Fallout 3. If they add in new enemies that are hard to kill, perks that aren't completely broken and they have the skill points per level cut down by two per level lowering it from 15 skill points with 10 INT (17 with Educated) to 13 points per level then it could be possible. I don't think the odds are good that they'll do that though so this is probably a bad idea for them to put it up to 50.
They should just have some enemies have perks to go against you're own. Like if you have the "Hit the Deck" perk, they could have something that just increases the damage of their own explosions, or if you have "Adamantium Skeleton", they could have a perk that gives them bonus limb damage. That way, there would still be enemies that you would hesitate to just run up and punch with a Ballistic Fist (which is pretty much all I use at Level 35). Skill points, however, don't really need tweaking. Even if they do what you propose, I could still easily hit 100 in all my skills, with just 2 more level raising DLC's, let alone the 3 I predict. Granted, I would have to hope that there's another set of Skill Books, like Dead Money, but I'm not too worried. And on top of all of that, I would be completely unsurprised if there was a perk akin to "Almost Perfect" that would go with a DLC that made the Level cap 50.
Also, after some calculating, it seems that we would need 186,200 exp to hit Level 50, which is more than double the current 90,950 needed to hit 35. This makes it more of a challenge to get to 50, and would also necessitate much tougher foes that give much more exp.