The SQ-64 doesn't get me all that excited, tbh. It feels more like Korg's playing catch-up to everyone else with it, where there's already a big installed base of Arturia, Polyend, DSI, etc etc sequencers like it out there. And while some reviewers have pointed out that it has more tracks than the Beatstep Pro, that "more" actually amounts to "one", since track 4 on it is a trigger sequencer that only puts out 8 (16 over MIDI) pulse channels. Also, the BSP doesn't involve massive menu diving...and that Korg has one of those ominous, Roland-esque alpha displays on there, implying that it does.
The vibe I get from this is that it likely has something to do with the 2600 mess (three CV tracks, three VCOs...?), as it was intended for release in May of this year, and it would've filled the gap that not having the 1601 Sequencer reissued caused. But whether this indicates that Korg's preparing to drop the "2600 for the 'unconnected' peons" at whatever Winter NAMM 2021's going to look like, or it's just leftovers from that screw-up from 2020, it's hard to say.
Might make a good match for a Behringer 2600, tho!