About removing oasago2, I disapprove strongly, but I strongly approve your point of making the game more fun with more variety in the maps chosen by the players.
But removing a map because it is too popular, is really a bad idea. It will only disturb and provoke anger to the players used to play this map, and will give an unfair advantage to the players who trained to other maps. This map has no reason to be excluded, because if it is because of popularity, then we have to ban out many other maps like ps37ctf and pul1ctf which are way too much played now, as oasago2...
Even if I'm against removing it, I think it's a pretty good idea to replace it by a completely equivalent reworked map for better performance, so all players will all have the fairest chances.
We can also add some alternative, remake maps of oasago2 in addition to the original oasago2, because it's really unfair for people to enter a competition and learn on the grill that their fav map was replaced by a completely different remake ! Remakes are good, but I would be highly displeased if it had to replace my fav map. See aggressor++ in tournament, and all aggressor remakes, they are very very good and I loved to play them, but it couldn't ever replace the original aggressor map, whatever distractors could say. For proof, the original map is still in tournament servers rotation, not aggressor++ which is now really rare to see.
Anyway, we could maybe add a rule to the league, to restrict the use of the same map only once per clanmatch, I mean if one choose oasago2 then the other will have to choose another (and we don't care if the opposite clan is also a fan of oasago2, the map choosing first has to assume and predict its enemy, plus this case can happen with any map).
Just my point of view on the subject. Ill try the remakes, they seem to gather unanimity amongst all testers