A lot of people have tried to suggest various versions of mana gain in the past through making maps. Personally, I am against this.
I think that the Mapper rank (which gives VIP perks on Parkour + the plots) is quite the incentive for people (especially without ranks) to make maps on ManaCube. There's also incentive to create an original theme and stunning build through Map making with the Featured Maps update, which brought the Featured tag, monthly voting, and 500 Mana to the winner as a repeated reward if they already have the tag. I think that's the extent I see for mana gain from map making. Ultimately, this is a parkour server--I think it defeats the purpose if you can rank up from making maps over doing parkour.
If I received mana from my 30 maps accepted, I would have received:
9 Easy Maps: 900 Mana
7 Medium Maps: 1750 Mana
6 Hard Maps: 2250 Mana
4 Expert Maps: 2000 Mana
4 Insane Maps: 4000 Mana
For a total of 10,900 Mana. That's quite a bit-- to be fair, there aren't many mappers with as many maps as I have
but Shinx and Presidenten (to name two of the high map count mappers) have over or almost double the maps I have (and I would guess they have made more high difficulty maps, resulting in more mana). That's quite a bit! I believe that amount of mana could pretty easily put me at the Pro rank if I wasn't parkouring at all, and only making maps.
I also think it's easy to forget that there's some unintentional community prestige that comes with gaining the mapper rank-- I know that once I got that tag, people noticed me more, it was much easier to get my maps tested, and I was able to collaborate with other mappers more frequently. When parkour chat moves really fast, I know that it's difficult sometimes to see what's happening...and that purple tag really POPS OUT.
I think more perks should come with gaining the Mapper+ rank which can hopefully be added at some point :) but that's for another time and place for me to explain.