> I'll just take an example of something that matters to me in particular: since > multithreading was removed GroovyMAME has been down in the mud.
Just stumbled upon this. This is simply not true. The reasons for the stall are rather mundane. Lots at work at this part of the year, and the very little free time I have for this has gone into adding a few things into baseline. Stalls like this have happened in the past but now it's more obvious due to MAME's update schedule. Some of us have very standard lives with kids and stuff and just create nicks like this to release the nerd in us.
It's true that when some important overhaul happens in baseline, I need to stop, take perspective and decide how to follow. The new licensing, the BGFX renderer, and more importantly the possibility to merge GM, these are big events that need careful reflection.
If -mt was so fundamental to GM I'd have raised some objections to removing it. In fact I've been one of the critics of old -mt, you can see it if you dig in BYOAC. GM used a different implementation all the time, so now what I've done is to make it independent of baseline -mt, that's all.
Finally, with regards to command line etc., please learn command line my friend, don't blame other people. That said, I don't see why mame.ini couldn't be just packed in the zip like anything else.