Moddability would be great, but iirc they kinda wanted to avoid to promise anything. I don't think it's because they want sell DLC, modders and mod users as hardcore fans are probably more likely to buy any DLC anyway, but because they didn't want to promise anything which they don't have time / resources allocated for and viability checked.
Thing is that modding is the dominant function since all other functionality that players are asking for (localization support, new/different mechanics, new content, rebalancing etc) can in principle be done through mods.
Did you guys look inside DATA_001? Sounds, music and graphics are in plain format. You can use gimp for example to replace all humans faces with goblin ones and vice versa making your company/humans and brigands a goblins when humans running a gorilla warfare against you.
Then there are scripts. Ar neatly divided and separated. There is script for night time effects for example. Or double grip. Each perk, background, item, trait etc is a separate script. Now its probably fairly easy to modify them( want to add +10% to damage for strong? look at Drunkard and stole it from there), bring back old perks(from older builds), modify or add items but.. they are all in compiled file format and there is nothing you can do to modify them.
For example you can just insert changed gfx file into original data_001 file and it just works.
Anyway all you need is the tool that is used to compile/recompile scripts and you are set for green pastures.
If not financial reasons are behind it then what?
Did they not see potential that is associated with modding? Kind of hard to believe that.
Maye it was sponsor condition(but that files structure are way back before they acquire one).
So either its financial(they wanted to milk it for DLC and expansions) or ideological ones(its German studio), maybe even anti piracy measure(as some sort of drm).
Dunno.
Anyway plenty of stuff, balance and world tuning could be done with mods and what is better it would keep game alive. Now probably in month the forums will be all dead and empty.
Sad.