I never got to play it on PSP, mine had broke right around the time Peace Walker came out so I ended having to weight and play it on the HD releases on PS3. For a portable device the format is perfect, I just hope for Current gen systems it's a little bit more interactive. I'd like to be able to walk around mother base as Big Boss and give commands and orders of what I want done, as opposed to doing everything from a menu.
Peace Walker's biggest crime was the story and boss battles in my opinion, if TPP is better in those areas then it should be great, to me at least.
I forgot about Olga for some reason, I did enjoy that boss battle, Solidus was good too but compared to the rest of the series they felt very generic and unimaginative. They're still good though and better than most bosses from other games so I shouldn't complain.