To me, PoB would be people that are not bots who are posting/commenting legitimately(not spamming/not begging for upvotes/not stealing content/etc).
50/50 has longterm problems with whales not distributing their power overtime and instead keeping themselves whales.
75/25
A whale with 1 million HP, lets say his weekly outgoing upvotes add up to 2,000 USD total, 1,500 for who he upvotes and 500 for himself.
50/50
Same sitiuation, but now he gets 1,000 USD a week to himself and 1,000 to authors.
Under 50/50 his whale position remains relatively static in terms of his overall ownership of the % of HP on the network in total. Under 75/25 everyday that whale loses his % of total HP owned.
I see that as a big issue, entrenched stakeholders who stay that way. Power corrupts absolutely, I believe I heard that somewhere ;)