It's been just over a year since we swapped our Altis server over to Tanoa (much to the disgust of some players, so i won't please everyone) and I have been mentioning for quite some time that i intend on swapping our Tanoa Wasteland server over to Malden once it is released. This new map is due to land on the 22nd June so on or near this release i will be swapping the maps/mission over.
Tanoa in my opinion was a nice edition however it sits behind a paywall and as such most casual arma players (such as wasteland players) don't own that DLC so it would never be busy like Stratis.
anyhow, Malden - my first impressions are that this will fit very nicely with wasteland, it's bigger than stratis but not a huge as Altis. if you want to check Malden out now it is available on the arma 3 dev branch.