Can't say I didn't see this coming. The signs were there. Oda seems to be wanting only Akainu vs Luffy afterall. Could have had Kizaru go up against another top tier or something if he was saving Luffy for Akainu. Shaping up to be a waste of arguably the most powerful logia because Oda doesn't want to draw serious fights against top tiers knowing it would take too long and too much effort to draw, and it would halt the rest of the stuff he actually wants to draw (especially if Luffy is to defeat someone on the same level anyway in actual focused battle).
His answer to this problem was to muddy up egghead with the constant G5 overuse (so Luffy can deal with things quickly), Kizaru's "internal dilemma", and the focus on anything but Luffy for Kizaru (again so Oda can excuse Kizaru being timed out here and there while having an excuse). Oda knows Kizaru is too strong to lose quickly which is why you don't see any signs of physical defeat (he hardly shed a drop of blood the entire arc), and why he refuses to have Kizaru lock in on Luffy, why he has Luffy taking potshots the entire time to down him whenever convenient for the plot. Just another case of Oda trying to have his cake and eat it too.
Good chance Oda has made his choice, Kaidou from the Yonkou and Akainu from the Admirals, the strongest from each group which is as good as Luffy beating the rest so he doesn't have to draw "redundant" long fights. (Teach is exempt from this equation, he's not a part of the OG group, just as he wasn't really a part of the Warlords, he's just using these titles to further his own agenda).
If Kizaru vs Luffy doesn't actually happen this arc, it is all but Oda admitting Luffy is going to be taking Akainu down. Believe it or not Luffy beating Kizaru here would significantly reduce the chances of an Akainu vs Luffy with a conclusion.