Hi,
We removed Gremlin-Scala from the mainline distribution of Gremlin because no one was maintaining it and desired features were not being addressed.
"Why not just review the pull-request?" -- because that takes time and I'm not competent with Scala. Therefore, if someone is more competent with Scala (e.g. you) and wants to make Gremlin-Scala superb, then that is great and you should have full power over Gremlin-Scala instead of me (or another TinkerPopper). From there, we can then advertise your Gremlin implementation via documentation, provide support view gremlin-users, and Tweet/etc. about it.
In essence, I would not fork Tinkubator but start you own project called Gremlin-Scala. You are free to take the source code (its BSD) and grow Gremlin-Scala as you see fit.
Make sense?,
Marko.