It was nice seeing that Ringo took Simca out of the fighting only temporarily, and she's not quite the evil bitch we had thought she became. She was actually protecting Simca, who has no combative abilities whatsoever.
It does seem like it's reaching the beginning of its final arc, but there are too many unanswered questions, a couple of them about Tool Tou To.
-Nakajima (I think that's the name of the other girl that always hangs around them, Emily's best friend) was shown to have the same pefect sense of timing as the tuners, and she lives in a repair shop. Where will she be incorporated into the storyline?
-What conclusion will be reached with Kururu and the girl fighting with her over Ikki? Will the regalia breaking be used to try and show Kururu is incompetent (since it obviously was not superior to the ones Kururu made).
-Why Simca left Tool Tou To, or at least the exact circumstances behind it.
-During the end of Ikki's hospital stay, they implied Emily developed an ultimate attack on a parallel schedule, the one that displayed how many panties Ikki had seen running on his hands. Are they just going to gloss over it, or will we actually see it? We saw Onigiri's lame and perverted skills after all.
But just because Ikki is leaving doesn't mean the conclusion will start. Ikki realized that the path he was taking was the exact opposite of his intention. Taking down Trompheaum (sp?) using the Wind Regalia would not give him the freedom he wanted all Storm Riders to share. I think it's more likely that AirGear is just about to make a fundamental shift in the story. If you read Tenjou Tenge, you might see similar things happen before the story shifted and got 20 times as confusing.
Fake climaxes are fairly characteristic in Oh! Great's longer works (pun absolutely intended).