What i think is that f2p events, generally speaking, aren't much friendly towards f2p players.

Take a look at sakura's gift event we just got. That event would have been marvelous for free to play players if sakura gave out not 1 but 5-10 missions per day (and so 25-50 food sacks). The problem is only that one. A f2p player got out of that event, maybe, 10-15 cave keys or 1 charm pack out of a whole week. Is too low for them to be satisfied and is right they aren't because they know they aren't getting any concrete chance to grow in power.

Oasis wants really to try to change? Then every single event that gives free things should give 4-5-6 times the current free things it gives and events where you are required to spend coupons are not if you don't have the chance to gather them.

Yep, but they cost 125 coupons xd.