Filler? I don't even know 'er! aka the fuck-Bleach [SPOILERS] megathread!

[Sithdarth]

then wouldn't this make vizards inherently better then arrancars?

Only imperfectly made arrancars which I assume is what they went with to prevent them from becoming stupidly strong. I'd imagine with enough research and effort you could get a shikai and bankai using released state arrancar. Of course it would probably take a Vasto Lordes level hollow to begin with and would result in something actually strong enough to challenge you for power.