Wolf is right tbh, if you pay attention to the hologram Anakin's blade is actually furthest, in-front of Drallig's, having just being deflected by a block - the clash of their blades being audible. The hologram just makes it look like it's going through him. The fact that you can still hear their lightsabers clashing afterwards despite their being no Jedi immediately present reinforcing this. So it's likely the Legends interpretation is wrong here. Regardless assuming Cin died in that exchange it appeared to last no more than 8 seconds.
However though Drallig may have been the finest swordsman present, there is no evidence to suggest he rivals Ti or the B-Team in Force power. He's never been considered in their league before, so I don't know why we're starting now. Instead given that this isn't Vader's Canon prime, he's clearly outclassed in that regard, and incapable of competing with Anakin's Force strength & speed, hence the blitz.
More compelling evidence being that despite having just witnessed this, Yoda has no qualms in dispatching Kenobi to kill Vader. Despite telling him that he is not "strong enough" to face Darth Sidious. Whereas by the logic of the OP, Yoda would be knowingly sending Kenobi to his death - arguably better off against the Emperor. It just doesn't hold water. And as for those who have forgotten:
Originally posted by BeniboyblingPack it up Anakin brigade, this party's over. 🙂
"This is Vader in his prime. You've got to remember how far we've come from the character when he was Anakin, he has so buried the good person that he was. There's no reason for it to come out yet until he get's exposed to Luke." -- Pablo Hidalgo, Rebels Recon