Ha ha-great arcane Colt style points! Realistically, I don't think anyone is yearning for the collet bushing (and CNC controlled manufacturing tolerances has eliminated the need for them). I don't personally get bent around the axle (every pun intended) about the traditional versus the currently modified location Colt is using for the slide notch placement, and as long as the rollmarkings are tastefully done (and preferably with the rampant pony) and apropos, I'm fine with that, too.
Basically, I think that the basic Series 70 Reproductions were fine; reportedly, Colt is vacillating on whether or not to keep them in their line-up or just concentrate on the new Classic, which is basically a rebadged Series 80 without a FPS. My druthers for a relatively minor, but I think important improvement would be for them to concentrate on a mild slide and frame dehorning, either in regards to the Series 70 Repro or Classic.
25 LPI frontstrap checkering would be nice, but operationally there are some excellent alternatives, some of them arguably more aesthetically desirable than other for providing increased frontstrap grip (or providing an effective work-around). The Wilson foil checkering piece and /or Pierce rubber frontstrap fingergroove insert come to mind, as do adhesive applique pieces for the frontstrap. The work-around that I've personally is to go with a good set of G10 grips, as the inherent chalky grippiness of the G10 material offsets the relative slipperiness of a bald frontstrap.
Colt has come up with some interesting variations; the problem with Colt is in determining which are orderable SKUs and which are simply the results of what appears to be episodic parts-bin clean-outs. I'd prefer there to be an orderable model in the line-up, at least for a year or two.
Best, Jon