Is worth play MoP on Warmane?

I would like start with a friend on a MoP Server. Is it worth play on Frostwolf?

MOP servers are few. Frostwolf is bad, but other ones are too (dont expect vanilla-wotlk optimization).

taking into account that is 7x exp, you dont lose much trying.

If I have to be honest with you, don't try MOP at all. Outside of 90 pvp, MOP servers in general dont offer enough population and the optimization in 90% of the servers is awful for questing and even max level content, frostwolf included.

I would say yes, except Warmane doesn't really care to fix or do anything with Frostwolf so, no. Unless you wanna do PVP only.