1) Yoru > current emma, there is no denying of that. So if zoro can achieve the same mastery of yoru as he has for emma, then undoubtedly it will increase his AP.
2) However, Yoru seems to be more fitted as a 2-handed weapon, give its sheer size and how Mihawk often uses it with 2 hands. This leads me to think that a true mastery of yoru will come with the sacrifice of santoryu