I think RAScoms are pretty balanced where they're at. They're quite a large investment and they don't start snowballing until you have a handful of them. If you really want to nerf them i'd do something like halve their bp so they can't be both eco machines and fast base builders, because at the moment there is pretty much no need for engineers once rascoms start rolling out. In the current meta rascoms make more power than they really need and you can use the surplus to spam fabs with rascom bp which makes them even better. I think another way to nerf them would be to make their energy yield less than the power/mass ratio that's spent to build them, so you still need to make pgens if you are dumping your entire eco into gateways.

personally I think they're fine, but a lot of you seem to have a problem with them