I have been playing RPG's since Ultima 1 so I have been around for quite a while. Firstly I think Pillars of Eternity is a great game and nearly has got it spot on when it comes to an RPG.
Strongholds- The concept I have seen before and it is so nearly right. If in later updates you do the following it would be perfect.
Construction of Building- Lets see them being actually built, the wagons coming in and the workers putting up walls etc to add to the realism to the game.
lets make all constructed types have an active roll. For example the training area actually being used (not sure if it is at the moment) and the gardens etc. rather than just having a bonus perk.
Stronghold attacks - If by creatures from the Endless paths we should have defenses to stop them accessing first level of Endless Paths, if other attackers lets have them attack the Stronghold from outside it and we can then put into use all those defenses we paid for and even add additional elements like defensive weapons etc. Some would say this is more Strategy than RPG but it would certainly add another dimension to Stronghold and make it more purposeful.
Hirelings- More occupations not just wayfaring hirelings but servants, gardeners etc. We wan to see an active community in the Stronghold.
Equipping Hirelings - we got all that good gear and wish to put it to use?
Lastly the only other thing I would like to see is the NPC's more active in the game, going on their daily business and not just standing their 24/7 night and day doing nothing.
Thanks for listening