We are currently using tiled for the game we are working on and we noticed that as tiled is growing larger and larger there are way more things we can add directly on a tiled map, more information that is easy to access for programmers.
Most of times adding a lot of stuff in tiled requires a large number of layers of many different kinds, so my suggestion is this:
Why not add a folder system for the layers in the similar vein of photoshop folder system?
That would allow to enable or disable a big number of layers at once and would speed up map editing if your map has grown too complex, specially with the new tile layer offset setting.
Right now we are working with 20 to 30 something layers for each map, I don’t know if other developers that use tiled end up with these big numbers but it’s an eye-melting task to navigate through layers some times