One of the annoying module insertion scenarios I've often encountered is when playing SE. Each miner wants 2 efficiency modules, but doing things the "easy" way with Even Distribution or Module Inserter Simplified results in every miner receiving 3 efficiency 1 modules. Is there any chance of a feature for inserting a set number of modules rather than filling the machine? e.g. insert only 2 eff1 modules

Well you can right-click drag to insert only 1 module. So do that twice and now you have 2. Since you have all 4 options of insert-all, remove-all, insert-one, remove-one, it is pretty easy to make any combination of modules you like without having to preset a configuration. If you find it too annoying to do this regularly, then you should also install Module Inserter Extended.

oh nice, I had no idea about the right-click drag!

...did you not read the new pop-up window? :(

I vaguely noticed it, but I've been using MIS a fair bit before it was added, so just not in the habit of looking at it. However it also turns out that my jetpack fuel UI was covering the parts that discussed this feature ;p