Well they can make more maps for sure if they think its worth it. The rest of your suggestion sounds like a version of server transfer. The way the game works with the server tho, the server can only have one map loaded at a time because multiple players are potentially using it. In a single player experience, yes multiple maps could just load in and out as needed but not for multiplayer. That would then require a server for every map. The only way it wouldnt is if instead of one large “map” the 8x8 playable area were divvied up into smaller maps that were <=8x8. This is in essence what the dungeons are (a good example is the sunken city). To go from an EL map from Siptah (or to a new map) would require additional servers.
Not to say that isnt possible, but you can imagine that with funcom servers and the issue of server transfer being unavailable at this time, its not a simple ask. Also players hosting their own servers would have to have multiple to cover all the maps simultaneously, something a lot of people do, but because we use mods to accomplish it at the known resource requirements
So possible yes, but with caveats.