Yeah, it’s a beast of a feature. Studio One’s attempt, wonderfully ambitious as it is, ended up making it useless for me (unfreeze crashes and the negation of “shared copies”). Which is why I’m back to Cubase.
I think it’s not so much Steinberg has tried and failed, as they have too many other, structural, features related to Tracks that needed to be sussed out. I.e., the new multi-outs in 7.5 (a very welcome feature).
They’re getting there. I’m not a betting man, but here’s my wild guess at a roadmap:
v8.0: Bounce-in-place arrives. It probably doesn’t handle tracks with multi-outs, at this point.
v8.x (Pre 8.5): Bounce-in-place supports multi-outs.
v8.5: More “Print from bus” workflows appear. 8 insert limit finally removed. 
(hey, this is my fantasy roadmap, I can put in it what I choose.)
v9.0: We might see multi-select freeze / unfreeze (a.k.a. “batch” freeze) finally at this point. It would probably work with multi-out, too, since that code would have been nicely refactored from bounce-in-place.
v9.5: The rearrangement of frozen tracks, but it’s not reversible. Basically, a multi-select bounce-in-place. Everyone rejoices, those who don’t care about reversing back to MIDI, claim victory. Steinberg takes a small rest…
v10: Tons of other features not related to frozen tracks. All the stuff the marketing dept. wanted that was put on hold. (full multi-touch and high-density display features added at this point. 
)
v10.5: Steinberg doubles-down on other marketing-y features, goes after FL Studio and Ableton. Those wanting full frozen track reversibility are getting more vocal in the forums.
v11: Massive launch with full rearrangement of frozen tracks, full reversibility of frozen tracks with no loss of fidelity (i.e., aliased/shared midi regions, or multi-out assignments, insert settings, etc.)
At this point all other users on other DAWs switch to Cubase. Steinberg re-hires the Studio One team and announces plans for “Cubase One,” a new initiative aimed at touch-platforms and integrating Studio One’s MIDI controller assignment workflow.
wakes up from dream – gets back to making actual music with already amazing tools