For DLC I'd like to see the content for each of the factions expanded,

In my case I'd especially like to see new narratives added that take place after the main story. For example, after becoming head of the institute, there's so much there that's ripe to be expanded upon. Do you use your influence to guide the institute down a better path, maybe one that includes helping the people of the commonwealth, or do you help them with their existing policy of furthering their own agenda at the expense of the commonwealth? It seems like it's a common problem with Bethesda story arcs. They always end right as things are getting interesting. For example, you'd think that being the arch-mage of Winterhold would open up the possibilities of adventures that would rival the adventure that brought you to being the arch-mage in the first place but instead all you've really opened up is the possibility of getting a few quests helping Tolfdir find his glasses. Really, it always seems like you're expected to move onto something else and the fact that you're the leader of a particular faction becomes entirely irrelevant. It would be nice, for once, to actually get to play out the story in a meaningful way as the head of something cool without it being just an arbitrary thing that makes little difference.

Back to the institute. Imagine the fun that being the head of the institute opens up! Getting to choose what the institute scientists research seems like fun. What if you want to explore sinister research avenues that open up quests related to the research? Say for example you decided you wanted to reopen the research into FEV and that would involve snatching up innocents to use as test subjects and infect them and observe the changes as they turn into super mutants. There's so much potential for interesting stories. There's the possibility to just be diabolical, or the option to try to use the institute to do good by pursuing an ethical agenda instead.. what if you wanted to deliberately turn a blind eye to synths escaping so that those who desired to leave had an out, what if coming down hard and shutting down any possibility of escape for synths instead leads to having to deal with more direct rebellion from the synths.

As the director of the institute you should totally be able to occasionally order synth bodyguards to beam to your location. You should also be able to bring anyone you want into the instutute. Is there any reason why the director couldn't get clearance to bring piper. That would be fun. Would it be good PR or would it be a disaster, or would the board members veto the idea?

There should be side benefits to each of the factions. For the institute, instantaneous fast travel should become available so you can take advantage of the institutes teleportation capabilites, There's something kinda satisfying about landing on scene via lightning bolt, and there shouldn't be any reason why it can't be used by the director to get around the commonwealth faster.