To be honest the whole companion system in the game is thoroughly shallow. I was expecting at least some companion quests like in New Vegas. It would've been a lot better if they wouldn't court you (or vice versa) until you'd proven your loyalty and done their quest instead of just "ooh shiny amulet, me love you now". Although I think I'd be pretty heartbroken if Vorstag turned around and told me he really liked me just not in that way.
I loved the companion quests in New Vegas, and it would have been great to have them here. The reward being a nice upgrade to their stats, or weapons.
Even better, like New Vegas, companions should supply you with a specific perk.
Boone in New Vegas had spotter, I think. Made enemies glow?
So, Aela could have a similar perk provided to you, that would basically give you a permanent detect life effect (only for enemies, though. Would get annoying seeing everyone in town glowing).
Correct me if I am wrong, but enemies don't show up on your compass as red dots until they're in attack mode, right? Well, another useful companion perk would be having enemies show up on your compass, even when they aren't in attack mode.