1. If you can't build troll cages or some advanced military buildings iot's not a bug. Would be 2 events ~on 50 and 100 turns

2. If you capture a settlement annd can't recruit tropps while proper buildings are existed - you don't have enough "native" culture in settlement. It should be for militia/regulars/elite:
a) Most of factions - 10/25/50%
b) Elves and dwarves - 15/30/60%

3. Elves and Dwarves have such numbers/pop.growth/stats because of balance. Wait for second release better than asking questions like "Why elves breed like bunnies" and trying to balance their forces