The worst thing about the switchaxe in my opinion is that it stops having good upgrades until god knows when. I am stuck on Barroth because he moves too much to hit his fleshy bits, and the bone axe + has the wimpiest sliver of green sharpness ever, making sure that you can't hit him anywhere but his underbelly or tail.
The next possible upgrade you can get for the bone axe uses Barroth materials, and it gives -20% affinity.
The trick to Barroth is to not fight him when he's enraged. As soon as he starts blowing steam, just run and keep running. If you have to wait off screen for a while, do so. He'll heal every now and again, but never by much. He's way too fast to fight effectively when he's mad, though. Of all the wyverns I've fought in this game and the ps2 game, he's the most unforgiving when he is pissed off.
The caveat to this is, if you can get his tail off, he's actually pretty easy to fight enraged, lower attack range. The downside is that getting off the tail is nearly impossible because whenever you knock mud loose off any part of his body, he's likely to become enraged.
edit; So I beat Lagiacrus; Really not that hard of a fight, to be honest. Rathian/Rathalos are considerably harder, as they don't have as predictable attack patterns. I don't know if it's just becuase I'm a lancer or what, but none of the leviathans have been particularly challenging, I seem to have no trouble consistently attacking anything when I'm in the water.
