I for one would love such functionality, as I am ever in flux about my squad, and am trying to level 3 teams of 5 so I can swap out n stuff. I'd love to be able to search by cast time, I made a macro that does "long" spells and one that does "short" ones, and achieved some good synergy with cast times (pyroblast takes a while, so I can get a long and a short from my priest/druid before the mage's big one goes down)

Ideally it would be a cool addon like Atlasloot, so I could look at spells in game on one wow window...