Tier 1 Perks are mainly based on countering the action of the enemy. I normally run Blind Eye so I'm not a target of Hunter Killer Drones and other AI killstreaks. I will modify some classes to run Flak Jacket instead if the enemy starts throwing explosives around the map. Or Ghost and a silencer if enemy UAV keeps popping up, but you have to continually be moving.
Tier 2 Perks are mainly useless in HC. Really you should be running Cold-Blooded about 95% of the time. Target finder is pretty commonly used and can sometimes diamond you up through walls even before you get close to an opening. The other Perk would be Fast Hands if you tend to use equipment in combat or switch weapons. It cuts down weapon switch time by 50% and equipment deploy time by 40%.
Tier 3 Perks to me is pretty important. Engineer should be a go to Perk. It's allows you to see where equipment are. And if people are placing down claymores, tactical insert, or shock charges, you can see where campers are set up. Also when you trip the equipment, there is a short time before it goes off. If you tend to sprint everywhere, dexterity is great to bring up your weapon to ADS quicker. Almost 3 times quicker. And if you're into sneaking, throw dead silence with your Ghost and Silencer class.