I've had a couple of 6.5x47s that were more picky than any other cartridge I've loaded for, and in the end, they both were one-trick ponies, only shooting well with one load, both liking the same load of IMR4007SSC & S123MKs. OTOH, I've had three other 6.5x47s that were no more picky than any other cartridge, and liked 107, 123, 130, & 140gr bullets, with a variety of powders. One of the really picky barrels was a factory fluted bbl for a DTA SRS rifle, the other was a fluted Krieger in med Palma contour; both were 1-8tw. A BAT 3L prone rifle that I barreled with another 1-8tw 30" med Palma (don't remember whether it was a Bartlein or Krieger at this point in time) shot really well with either 130VLDs or 140 LRBTs; shot several clean 600yd prone scores with high X-counts with that rifle, and some good (for me) scores in 1000yd any rifle prone matches. Also had a 28" Krieger on a Pierce TG action in an Eliseo RTS chassis that I shot in XC HP matches, where the shorter loaded length of the 6.5x47 worked well in AICS mags. I always thought the 6.5x47 was a top-notch XC cartridge.
I've also had Big Horn TL2-SA action-based PRS rifles in both 6.5x47 & 6.5-08 Improved 30*, and liked both quite a bit, although again, the shorter 6.5x47 allowed seating 130&140gr bullets out quite a bit longer than was possible with the 6.5-08 Imp. It's a bit of a wash trying to argue that one's better than the other in this application, although I believe the 6.5-08 Imp is running slightly less pressures for the same or slightly higher velocities relative to the 6.5x47. Do both chambers on two new barrels, and whatever advantage the 6.5-08 Imp may have over the 6.5x47 could be larger or smaller... I like both rounds.
Have only shot one 6.5CM, and it was an Aero Precision M5 (AR-10) with a 24" Krieger that I fitted & chambered. It shoots OK, but I built myself another AR-10 (on DPMS receivers) in 6.5x47 with a 28" Krieger that will out-shoot the one in 6.5CM by a considerable margin. Again, only two barrels - do it over again with two other barrels, and perhaps the accuracy results would be reversed... Point is, with a lot of experience with the 6.5x47 & 6.5-08 Imp 30*, I don't feel the need for a 6.5 Creedmoor.