It does, but only if you sprint first and then go into a slide. I think it should bee that if a slop is detected and you're walking it should be an auto slide, but that's just my preference.
For the floatiness, double the gravity and jump strength you currently have and see if it won't fell more responsive.
I get having switching direction mid air be a bit harder, but I think it's just a little too hard currently. A lot of the game is mid-air navigation, so a little more control would be nice.
Still, I genuinely do think that with some tweaks you movement engine could be incredible.