The NH-C12P was discontinued in favour of the NH-L12 which they consider it's successor. Unfortunately I believe there were concerns about it overhanging the board which would put it in conflict with other components.
If you're not happy with the C12 temps, do what I did today - put a better fan on it. I dremeled the annoying side walls of a Scythe Gentle Typhoon AP-29 (2150rpm) to allow the stock Noctua clips to work. With the Noctua ULNA adapter it's running at ~1270 rpm. Acoustics are about the same (slightly better) than the NF-P14r running without a resistance adapter and temps at stock 100% load on the 4770k are about 6 - 8 degrees cooler.
Keep in mind my build is not currently in the NCASE M1 (yet again) - waiting for the new SFX psu's from Silverstone.
If you're not happy with the C12 temps, do what I did today - put a better fan on it. I dremeled the annoying side walls of a Scythe Gentle Typhoon AP-29 (2150rpm) to allow the stock Noctua clips to work. With the Noctua ULNA adapter it's running at ~1270 rpm. Acoustics are about the same (slightly better) than the NF-P14r running without a resistance adapter and temps at stock 100% load on the 4770k are about 6 - 8 degrees cooler.
Keep in mind my build is not currently in the NCASE M1 (yet again) - waiting for the new SFX psu's from Silverstone.