This technique seems to be more limited than wavedashing as far as mobility is concerned. It seems that you can at least run away, then pivot to perform an attack while sliding away, and you might be able to do an attack while sliding forward by running forward, pivoting back, and then C-sticking forward. Unfortunately, dash dancing appears to be limited, so this will probably limit its versatility and mindgame potential. It'll still be incredibly useful, mind you, especially for characters like Marth, and has potential in other areas such as comboing. It does provide movement somewhat similar to wavedashing, though in a more limited form. This isn't the only instance of this, as tapping shield while running seems to produce a similar effect to crouch-cancelling a dash in Melee, though this is a bit slower too. Ultimately, I don't think Smash 4 will have movement options that feel quite as tight or are as versatile as Melee's, though they're sure to be leaps and bounds ahead of Brawl's.