It's an interesting idea, gluing to glass so you can remove it, I have been experimenting with gluing on to PVC packaging cut into small pieces to achieve a similar effect but leaving the pvc under the terrain piece because it 'disappears' on a board background.
I tend to agree with you that bases detract from fitting the terrain piece onto a board, it seems most people do a board one colour and terrain bases a different one, accentuating the difference.
The other thing that is really good is using natural materials, I don't understand why someone would buy a piece of dowel, distress it to look like a tree trunk, paint it to look like a tree trunk, it then looks like a piece of painted straight dowel, when they could go outside and cut off a piece of wood as you have done. It's much cheaper, simpler, and more effective to use a twig.
Hope I've not been too controversial.
Look forward to seeing more.