There are literally tons of things that successful coins need, beyond core development. Marketing and promotion are just one area. Supporting ecosystem items like games, dice sites, 3rd party block explorer, faucets, rich list, paper wallets, merchant contacts, and anything else you can think of would be useful and welcomed. These items are just examples to get started, and aren't in any particular order of utility.

A second PoW period is currently up for discussion. One way to balance an increase in coins is to reduce the amount of PoS interest, as seattletu has suggested.