We need Summoner Rift's skins based on regions.

Since the SR is the map layout that works best, one of the best solution for diversity is simply to make map skins instead of new maps that don't work as much/aren't as popular as Summoner's Rift. ######(Hello Twisted Treeline and Crystal Scar) Since Runeterra's visuals are being more and more developed, the best inspiration for skins that still correlate with the game are the different regions. In addition, players have expressed their desire to bring back the Crystal Scar and the Butcher's Bridge not only because it was in different and/or beloved game modes but also because they liked to play in a different environment than usual.

Seriously, imagine the SR in, say, Bilgewater, having some of the Butcher's Bridge's assests such as turrets, inhibitors, nexuses or even the shopkeepers. The map is the dangerous docks of Bilgewater at night. The jungle are the dark back-streets with only few lanterns to light them. The jungle monsters are replaced as well, Razorfins takes the place of Wolves, Raptors become Wharf Rats or even Nagakabouros instead of the Baron Nashor.

And digging a bit into what's been released in the Universe Website, any region is adaptable.

EDIT: Also, it would be one more good way to introduce the game's lore to neophytes.