Hey, only a quick update here.
I've just downloaded the beta for the new GameMaker Studio 2, and It looks sick!
They just fixed some things that bothered me about the GMS 1.4, the first is that you can maximize the window now (maybe it was only my problem with this). Next, the new workspace system is a los better to use, everything you want is inside there, and you can drag the screen to move arround, zoom out, etc. Inside the workspace will be all your old windows, rooms, object propeties, etc. having only a window to keep it all there, fullscreen or in cascade was a pain in the ass.
They eliminated the backgrounds as they were, but now you can use sprites without creating objects, and the rooms now have several layers, and even can play animations without having to launch the game!
I'm sure that, after I finish my upcoming game, I'll will be trying it a lot!
The beta right now only compiles to desktop application, and not commercial use though, but on future updates there will be other options to try.
P.S: And if you already have GMS there is a discount when GMS2 comes out.