Very interesting ideas.

Off the top of my head, I can think of a couple of issues that would make paying employees through Steemit problematic. First of all, the value of an upvote fluctuates because of the static reward pool, so it would be difficult to guarantee a particular salary. I suppose this might be mitigated by adding additional upvotes to make up for lost value if the payout decreased from expected.

Second, and a much bigger potential issue I would say, is the possibility of getting downvoted by an angry whale or a competitor wanting to mess around, which could wipe out an employees paycheck just like that.

But it would certainly would not surprise me if some opportunistic companies try it (or already have tried it).

I do believe this is a form of reward pool rape, and while I don't know if it is currently illegal, at some point when this type of system becomes more mainstream, laws will come into place to prevent such things. That brings up a whole other issue though. Laws are generally locationally specific. A country can make laws for its own citizens, but not for those of another country. With decentralization, no single country can enforce laws on the whole blockchain...

The next few years are going to be very interesting.