Holy jesus, the manga is on steroids now. o_0
1) So Head Baddie looks to be a giant raging douche willing to annihilate his subordinates for all his talk of peace. (And he's cruel, too - I felt sorry for Lost-Arm guy by the end of it all). It sounds like he's literally farming out Hueco Mundo as a source of soldiers? No wonder those guys looked like arrancar.
2) The nakama have gotten smarter. Ishida knows SS is misdirecting info to Ichigo; all Ichigo and the others can do is wait. At this point, given the state of affairs in SS and the five-day-countdown to destruction, it's probably best he's not in the middle of it yet.
3) Sasakibe died! Like died died, not shounen-died. Shit just got real.
4) ESPADA! Nel returns this chapter to warn Ichigo that something horrible's happened in Hueco Mundo, and Harribel shows up as a captive for the New Baddies. I find this interesting; it's well known in (English and Japanese) fandom that the popular Espada include Starrk, Grimmjow, and Ulquiorra. I imagine Kubo's building up to a huge reappearance of Grimmjow at the very least. And Ulquiorra too. I believe, I BELIEVE, DAMMIT, and I will not stop believing until the final arc is over.
This arc isn't going to go well for SS, is it? I have a feeling that five-day countdown is actually going to spawn a lot of destruction and that the shinigami are going to be in need of a savior - not just to fight someone on their behalf, but to save them. This actually makes the Fullbringer arc make a lot of sense in retrospect; if Ichigo's going to save the shinigami, his bonds with them needed to be reified and underscored thoroughly, and now they have been.
The pace is insane now. Wow.
P.S. People in fandom are pointing out--aptly--that Kubo made some comment (that sounded like a negative response to an interviewer's questions about the Espada) about how he really didn't think there was any way he could get Harribel "out" of HM. And here we are, and technically she's not "out" - she's in a dungeon, which may or may not be in HM. Which is further proof that Kubo is a sly, sly tease, and everything he's said to this point about who can and can't reappear is up for question.
P.S. Part 2: As many others have pointed out, a lot of people have claimed they couldn't find it plausible for the hollow to team up with the shinigami. But this could be a damn good way to do it.