Others have also made the point, but you can’t just mess with ELO like that. ELO should only ever take 2 things into account: game result (win/loss), ELO of players in game. If you introduce anything else it no longer works.
As an example: If player A (a pro) wins at 100% winrate but only every chooses Arabia, in your system they could be like 1050 ELO after 50 games. Player B (an intermediate player) chooses 20 maps, and is around 51% winrate after like 200 games, also at about 1050, and gets matched up with player A on Arabia. I think you can guess what happens in game at this point…
ELO should always be calculated to try and accurately match players on skill level.
You could hide ELO and still use it for matchmaking then introduce a new “points” system that works like you say - but it won’t work for matchmaking/ELO.
Regardless you’re going to ■■■■ people off, but the only other option if you stick with matchmaking is to get rid of Arena and BF and just have mainly open maps. Arena and BF are specialized play styles and if you have to ■■■■ of one group of players it should be the minority. Most people like Arabia and they will be ok with other open maps like Steppe, Gold Rush, team Acropolis, ghost lake, etc. You can include maps that have water like nomad but nothing that’s closed off or has choke points besides team islands which players can ban. Maps that are closed off with choke points is not how this game should be played at competitive levels. If you don’t want to incentivize through ELO, I think that’s the best solution.
At Tennis matches, a player may become Number 1, if play only at one court- Clay or Hard court. But if he play at a Tournament at other type court, usually he will lose at the beginning. So that player will not receive much money at Tournaments at other courts… I don’t see a problem if a player is Number 1 in the ranking, if he play ONLY one map. Firstly, he must find players, who want to play that map. If he find other players, he may receive points for a win. The players do NOT receive any money for staying at the top of the Ranking… But at Tournaments with PRIZE money at other maps, he will lose quickly. Also, at every Tournament, the Managers may chose and put the Ranking players at some seed place among 1 - 16 or 1-64. That player who play only ONE type map, may be seeded at the end of the seeded players, or even not included.
Well, then he won’t be rated 1000 on closed maps for long. If you use a fast converging rating system (like Gliko and unlike Elo), most people should be paired with a decent opposition after less than 3 consecutive wins as their very first match. For the 1600 player, it should be more like 2 wins before they face people roughly of their level.
So he’ll eventually be rated 1600 on open maps and say 1400 on closed ones and be paired accordingly. As opposed to the current system were he would be rated 1500 overall and have an edge on open maps and a disadvantage on closed ones.