Well...going offensive into the fight with Grievous, Obi-Wan would have force pushed him first instead of fighting him.
And considering the fact that TPM Obi-Wan with form IV was able to cut Maul's lightsaber into pieces and put Maul on his ass I'm pretty sure ROTS Obi-Wan using form IV would still kick Grievous.
And spins and twists don't make you an Ataru practitioner, man. Did you not read what I wrote above, Jack?
Uh, Soresu is not just how you swing your glowstick; it's a fighting philosophy. Obi-Wan was DEFENSIVE in his fight with Anakin. This is Soresu philosophy, not Ataru, which is OFFENSIVE.
If you paid more attention to what I post you might not be wrong most of the time.