Would love to see more map visual variety. But, I think they said in a Q&A in the last few months that it's not just a matter of throwing a Butcher's Bridge skin over the Howling Abyss map. It would take a lot more work on their end to make that happen, so probably not going to see that one restored any time soon.
They have the Holiday version of the Rift around Christmas which is nice. It'd be great if they followed up on that with an Autumn map to run from mid October to mid-late November. Leaves changing colors, wheat instead of grass bushes, a few jack-o-lanterns and maybe a turkey running around...
I wish Map Skins were a thing the way Champion Skins are. It would be the same Summoner's Rift or Howling Abyss layout and playing field, just with a different look and feel. These map skins could be based on locations in Runeterra, or inspired by various Champion skins. Like, a map skin based on the futuristic city we see associated with the PROJECT skins would be awesome.