So I am a HUGE fan of the dark brotherhood and enjoy committing heartless murder every chance I get. 
But I would like to see the dark brotherhood (as well as other guilds) expand on the after-guild quests some. For starters, I would like to get into the process of truly rebuilding the dark brotherhood. Pay money to have the Falkreath Sanctuary restored and filled with lots of dark brotherhood members as well as the dawnstart sanctuary. Also as listener, I have to be able to name my own speakers and silencers who will serve and do my bidding and restore order across the rest of Tamriel. There are people praying to the night mother in other provinces and they're prayers are not being answered because the sanctuaries are wiped out in those locations.
Also for the contracts, I would like to see some standards set on how the target should be killed such as no one witnessing the death of the target or the target has to be killed in a well-guarded fort without you alerting the guards. Implementing small challenges such as these would make the after-guild quests IMO that much more thrilling and enable you to gain bonuses in the process.
Lastly, make the targets much more interesting. For example, surely the temple of nine divines has a pope down in High rock and he's coming to visit the temple of nine divines. Would be fun to assassinate someone like him with all the guards around or you have to proceed down to Blackreach and chase your target amongst its underground tunnels.
Not really sure what should lie in store for the other guilds, any opinions on my topic?
