To be honest, I love your work regardless. Both styles (Multiple Layer and Single Layer) give incredibly different feelings and depth for the scenario. The newer style (single Layer) gives a more somber feel to darker scenery, and as a single background, gives brighter focus to the characters (or main focus). Multi-layered backgrounds, on the other hand, is something of awesomeness. True, it is difficult having all multi-layered backgrounds and characters, but the effort really shows in the end product.
In the end, I guess, I suppose it is
up to you, the artist, to go where you want from here. I voted Follow Your Dreams, Desu-Senpai~~~
because that's what I believe any artist should do. If you feel you can still make high-quality works all on single-layer, go for it. If you want to stick with multi-layered art, go for it, more power to you. Or, better yet, mix it up. No matter what you choose, everyone can, and furthermore should, choose and decide their own path. It'll all look good from here! Or there. Or over in that direction.
tl;dr: Ctrl + C, Ctrl + V, Follow Your Dreams, Desu-Senpai~~~
I tend to ramble sometimes, but it only happens when I'm passionate about something.