If I remember correctly, about 6-8 people work on code for singleplayer, and presumably the same amount in a separate team for multiplayer.
The 100 people is made up of scene artists, texture/model artists, sound artists/actual musicians (Ensemble Galatia), payroll and management, public relations/community management and bug report processing, maybe a dedicated writer, possibly other required people I'm forgetting, in addition to coders. Out of the coders you also have at least one (emrozdemir) working just on the UI. So probably 5-7 gameplay feature coders for SP. Each apparently has their own area, eg: Mexxico works on overworld economy, diplomacy, strategic AI code.
Of course it isn't necessarily a bad thing that a "small" amount of people work on the code, since a large amount of coders on a software project can cause confusion with multiple people making conflicting additions to the code; in that sense, having a lot of coders working on one project doesn't make things more efficient, in the same way that having a lot of people baking one cake stops speeding things up at a certain point.
So, Taleworlds' employees seem to be a fairly good number and well allocated. The question is why time gets wasted on things nobody asked for, while problems which the playerbase has been complaining about for a year remain unfixed.
According to Glassdoor reviews from former TW employees, there is very poor communication inside TW and a lack of planning, plus a few employees have a very relaxed attitude to getting things done (though others work very hard, even in their off time), plus the code refactor that was needed for a long time to make coding more efficient was delayed until last year. I think these have been the main cause of the delays over the last 9 years.
Agree 100%. And if they can't replicate the features they managed back when they actually were a tiny indie studio 10 years ago, then something is terribly wrong.