I hate Cazadors. It's not even that they're hard, it's that they're cheap.
They move too fast and erraticly to reliable take down in non-VATS combat, their poison is potent, and they're always in groups. More than that, they're so cheap as an enemy that they put me into positions as a player where I need to find a position they can't reach or another AI exploit strategy to deal with them.
The Deathclaw buff was okay, on the other hand, excepting that I think they move entirely too fast for an enemy that can slap half your HP out of you in a single swipe.
I love trying to tag Cazadors outside of VATS at distance, it gives me a chance to practice my sniping skills. One whack with a Trail Carbine and down they go. Yeah I burn ammo, but ammo's cheap and I have tons of it anyway.
When they close in, switch over to something that sprays a lot of lead quickly (Hunting Shotgun or even the Assault Carbine work well). They hit hard and they're fast, but they have no DT. Use that to your advantage.
As far as Deathclaws go, I like them the way they are in NV. They were ridiculously easy to dispatch in FO3. Hit them once with a Dart Gun and they became your play toys.