I've just installed and moded the hell out of oblivion and noticed something while playing, that skyrim does not have.
Obviously in skyrim you equip spells in either hand and in oblivion you simply raise your arm and a particle effect appears and you cast the spell.
Now what if a mod were to add that latter system into skyrim? I think it'd be great to either have new versions of existing spells or a new button/other way to cast a spell that doesn't require you to have nothing else in your hands. I heard there's some issues with animations so maybe the raising of the hand isn't possible but that's not the important part, right? Besides the bashing/attack animations can substitute that. To me this seems like a great way to improve the gameplay of combining spells and other forms of combat. Improving the 'spellsword.'

I'm no modder, so does anyone know how feasible this is? And how useful do you personally think it is?

Can't say about feasibility, but I personally like the Skyrim principle better (either item or spell). What I dislike about Skyrims Magic System is that there aren't enough hotkeys available to use it at it's full potential without having the favorite menu open all the time. Even with mods that give you more hotkeys it's still not better because there aren't that many keys on the keyboard that are conveniently reachable with your left hand.

There are some ideas for improvements floating around this forum but actually no one has started on something yet (I guess because it would involve use of SKSE and/or Script Dragon), at least no one announced it yet. What we have are a few mods that just add even more spells to the list to pollute your favorite menu on a magic char.

I myself haven't had any problem using 1-9 for magic hotkeys. But I haven't played a pure mage and can see it getting very cluttered with weapons/armor/shouts and not having enough buttons. But isn't that more of an issue with the keyboard and it's lack of buttons? I have a mouse-keyboard combined thingy lookin thing around here somewhere and never had a use for it. Maybe I could use it for extra hotkeys if I ever need more.

Though my idea was more for an extra way for more convenient casting and I don't see how it can help if you've got more spells than hotkeys.

http://skyrim.nexusmods.com/downloads/file.php?id=3865