Light Armor, currently, is probably the biggest let down thus far for me (especially being a player who loves stealth based/assassin-like classes). Not only does it just look like more versions of warrior-like armor that would be worn as a two-handed battle-ax wielding juggernaut, but there are very few types and version of it to begin with. The left side of the smithing tree, which is often referred to as the light armor side, is pointless to go spend perks into. Not only does it not have a wide variety (the right side has about 6 or 7 options), but you have to complete the right side as well to get Daedric Weapons. It is more frugal to spend your perks only in the right side of the tree and make do until you kill enough dragons to make dragonscale armor, which understandably looks more warrior-ish, but then again leaves out those of us who would love more stealth based armor in terms of looks.
Here are my suggestions:
1. Add more light-armor variants in the smithing tree: Even one or two more smithing perks, at least one of which that would be sitting on the 90 skill mark along with Daedric, that would open up options to craft assassin/thief-like armor would be great. This would include something along the lines of a cowl/face mask instead of an actual helmet, and armor that doesn't necessarily boast large and flamboyant shoulder pads and chest pieces. This would be the most preferable solution, in my opinion.
2. The option to learn how to make armor sets that are found/given: I.e. if I acquire a set of Nightingale armor, I can learn to craft similar looking armor, but in the process destroy the current set. This suggestion is far less favorable that number 1, but would nonetheless be an option.
3. The addition of clothing pieces to go over armor sets: This would include things like cloaks and capes, both hooded and unhooded (perhaps even an option to have your hood up or down). This is on my Skyrim-DLC Christmas list, but would only make sense if number 1 was implemented, in my opinion.
These are my thoughts on light-armor so far. Please feel free to give your opinions and suggestions as well!