I believe everyone in the community has realised the possibility of GAE and MG merging is pretty much zero.
But I fail to see why we can't join the efforts in developing the Map Editor and G3D viewer together. I know they devs themselves should have a say in this... and they may feel a bit reluctant to code for the other team etc. But really it would be much more helpful for everyone if we were using the same tools. Not to mention it's more efficient which would lead to quicker advancements for everyone.
I'm not trying to persuade the devs of either folk to work together, just offering a suggestion that I think would help the community.
