Wow, I didn't think it was actually in there:
So far none of the monsters is particularly tough with the exception of royal ludroths in water (the underwater combat is pretty awkward).
I really, really miss tigrex and yian garuga - they were some of the best fights in the series. Kushala daora was a good one too.
I still have yet to fight anything bigger than a barroth yet (really wicked charge on that - it was pretty neat to see such a fast charge after getting used to really slow diablos, gravios, and basarios charges).
Next one I'm slated for is a gobul. Gonna be kind of annoying I'm sure, considering it's another water fight.