Suggestions:
Steem’s main problem is account creation... How will Dapps grow if they can't register new users?
Other Problem, Curation... Why someone who upvote after everyone will gain less or nothing? It's make everyone vote to same peoples forever...

Or Maybe you make a system where everyone who have stake gain without need upvote like others POS... And give the possibility to upvote someone decreasing a little of the reward he would be entitled to.
Ex:
'User A' have right to 1000 Token per day, if he upvote at 100% 'user B' he will receive 900 Token that day!
Problems it solves: Milks and spam(Maybe)...

But the main thing is the website, because the end user has to have a great experience...