Kasan doesn't have much known experience here. Yeah she flew with Rogue Squadron and lead a TIE squadron, but we really don't know for how long or how well she actually performed in combat. Kenobi, on the other hand, has much more shown experience over the course of the Clone Wars. Of note, I'd like to point out his performances in AOTC and ROTS. He pilots a fragile starfighter through an asteroid belt pursued by a superior craft and manages to survive with only minimal damage. In ROTS, he flies through the crazy maelstrom that is the Battle of Coruscant, again only taking superficial damage. While I think Kasan is a solid pilot, I think that if she were in similar situations (AOTC, ROTS) she would not do as well as Kenobi, nor would she be called a "phenomenal pilot." I don't think Kasan brings enough to the table to best Kenobi here.