I think,hashing power of each worker and/or IP should be limited to not more than 50 MH/s
I agree. It did very well for Mineral, and is a nice way to avoid massive early dumps from big farms that are really harmful for the coin.
I don't see massive dumps as bad. There are many people who have no other way to get coins. In the end the market will drive the price whether it is mined by a farm or individuals.