DoC and NV are hardly the same, also NV healing for 100k? that means you hit for 400k, which unless you are whoring vengeance or have a dmg increase on the boss isn't going to happen. DoC will more consistantly save others, AND yourself if you use it correctly, but it requires you pay attention to your unit frames as well as doing all your regular tanking activities. I agree though that it is still kind of annoying without a dps increase OR being off the gcd. Additionally because the buff's duration is so short it's not 100% reliable for it to be up, i.e. you can't save the buff for too long, else it's wasted.
When comparing the talents in that tier we have:
HoTW: passive dmg increase with HUGE healing but on a long cooldown and duration, also an EH gain
NV: short cooldown burst dmg increase and healing for medium duration
DoC: Very short cooldown heal that Reduces the damage you output and is clunky to use. Either it needs to go the whole way and just be the go-to healing talent and have a longer duration buff and be off gcd, OR it needs to increase your dmg slightly to keep it in line with the other 2 specs. If the HT stays on the gcd, this dmg increase will have to be quite significant for it to overcome the dps loss sustained by casting the HTs, on the other hand that would then make it the best dmg talent by far if you were to not bother casting HTs (unless the dmg buff was somehow tied to the HT, similar to how DoC used to work, i.e. HT makes your next 2 mangles deal x% more dmg or something, or has 100% chance to reset cd of mangle, or makes your next lacerate extend thrash...or HT gives you a "savage roar" type buff...etc etc etc).
Essentially, atm NV and HoTW match and are along a similar theme for us and there is a proper choice. DoC just isn't in the right niche, doesn't line up with the theme of the tier entirely yet and is still clunky.