Rhino stomp looks somewhat jarring. Perhaps it'd look nicer if the melee slam movement was right on the "stomp" part, or simply making the stomp start up in the air and finish on the ground. Or even a combination of both. Likewise for Banshee, have her "ready up" in the air and slam down her palms once her feet touch the ground. It'd probably require some fiddling, though... In any case, the ability to freely cast in midair is definitely something that would give Warframe that much more fluidity. Think you can do the same for "two-handed" abilities that only really need one hand or neither (ie Link, Sonic Boom), and add mobile casting if it's relevant? Mag in her current state is a fantastic example of this, where she can cast 3 of her 4 abilities with one hand while moving. It really adds to the "ninja wizard" aspect of Warframe that's so unique to it.