"...by creating many, many new accounts someone could get easily a very big influence one the platform by doing many votes (or flags) with many accounts instead of a few heavy votes ... "
By preventing bots from doing this, the manual labor involved makes it unprofitable.
I reckon it's a moot point, however, as the actual market for Steemit isn't us, or even the whole world, but those 39 accounts that possess most of the Steem in the world. No changes that better distribute Steem seem to be desirable to that group, as a whole.
Bots are their best profit centers, and rewards their dividends. While the White Paper calls for disbursing ~30% of rewards to the hoi polloi, very few rewards inure to accounts that aren't whales.
Folks that are getting $.02 per post just have no dog in the fight. They don't even have a dog.
All the controversy regarding excessive rewards, returning rewards to the pool, self-voting, all of it, simply doesn't affect minnows. It's kinda like idolization of stars. Minnows are living vicariously through the whales, dreaming of ever having any rewards to guard from greedy self-voters.
All the flags on the platform in a month return about 5% of rewards to the pool. 5% of $.02 doesn't even register. None of this matters to minnows in real terms, just like Kardashians' love lives.