@Joe:
I doubt they will replicate all of the original PCB's slowdown (they certainly didn't do that in SDOJ EXA), and of course you get the original 240p graphics. So if you care about those things and own the PCBs then it shouldn't matter if an EXA version is released except if you want to play the new arrange mode.
With that said, the AK PCB, in my experience (and opinion), has far too much slowdown. So much that it started to irritate me whenever I played ST4 and ST5 because most of the time it feels like you are swimming underwater or something. This and DFK BL are two cases where I prefer the X360 ports. If they could just add in a bit more of the PCB's slowdown in ST5 and (especially) on the ST5 boss in EXA label (as compared to the X360 port), it would be the ultimate version IMO.