I remember playing Wasteland on Altis and it being a massive map for this gamemode.
When I came to SG Wasteland on Stratis felt... confined, cramped, like you had very little time to get yourself setup before losing it all in a firefight.
My opinion is to develop Wasteland for Malden, as it's free DLC so no barriers to entry and this change would increase playercount just for curiosity.
If, and I don't think this will happen, but if Malden becomes less popular that Stratis that map is already developed and you can look at rolling it back later.