3x is probably too much for my liking 2x or 1.5x might get me to vote on it.
maybe something fun like: ability for it to summon another card that gets half PP (but limited to the PP of the summoner itself) but i worry that could be extra work probably mostly for UX team to fit in the 6th or possibly 7th card. 

Just to give an example there are lots of people with GFL beta summoners that would jump their value from 50k PP to 150k PP... I think that would be likely game breaking. The alphas aren't as big of a deal since there is only one of them and very few people who have a maxxed version. But quite a few of us that have the various maxxed beta summoners. 
150k * 4.5 bonus multiplier would just be really really crazy

I think once we come out with our next PP feature people will understand what happens with some of these multipliers