There's a lot of core elements of CO's design that correlate well with having healing powers. In any game, self-heals are effective, and unless they perform poorly, they tend to be highly valued. When a hero can select any powers, heals just naturally gravitate to the top of the list. But there are a few other things that make this pattern more significant.
Attacks aren't that good
The conventional wisdom in Champions Online is to focus heavily on a very small number of powerful attacks. A well-built free-form character has between two and four attacks that handle the majority of situations. Characters might have a few more attacks than this, but these attacks tend to be situational or not actually present for damage purposes. As an example, a Might character has roughly three main attacks (Roomsweeper, Havoc Stomp and Haymaker, as an example). We can add Demolish for debuffing and Mighty Leap for closing distance and/or removing travel powers. In this example, Roomsweeper isn't even really an attack either; it's a way of maintaining Enrage, but Might heroes use it rather frequently, while the other attacks are only used when a situation arises where they're needed.
It's simply not really worth it to take much more than that; even taking Roomsweeper and Demolish is sort of optional in this setup. Haymaker covers single enemies, Havoc Stomp deals with groups (and builds Enrage), and Mighty Leap closes distance to the enemy. There's no reason to take extra attacks, unless you want pet powers that can fight simultaneously while you're clobbering.
I'm not implying that the power balance is that bad. There are certainly bad powers in CO, but the problem is that you just don't need more than a few choice ones. You can blast through foes in a lot of different ways, but there's not much point to take Chain Lightning and Lightning Storm and Gigabolt all at the same time. The problem is redundancy. For instance, Snow Storm, Avalanche, and Frost Breath are all pretty good, but there's no reason to have all three in the same build because they all do similar things.
Other games either force us to take redundant attacks that we don't use, or give us a lot of situational attacks that are very context-specific. We might have attacks that take advantage of debuffs, or have long cooldowns but are highly devastating. Sadly, these kind of attacks in CO just aren't good enough to warrant taking unless they are useful as main attacks.
Because choosing lots of attacks is a poor decision, it makes taking utility powers more valuable. Although there are other utility powers to choose, heals are high on the list.
Heroes in Champions Online have a fair bit of health. I'm not referring to the actual HP number; obviously characters in CO have thousands of HP, which is far more than Guild Wars and far less than World of Warcraft. In terms of actual health, though, the average Champion is pretty tough. Enemies do low amounts of damage -- typically around 100-200 dps at level 40 -- and are only really threatening in huge groups. Even boss encounters tend to not be very threatening unless lots of mobs are backing the boss up.
Although this could mean that heals aren't necessary, in practice the game is tough enough (especially on harder difficulty settings) that having a burst of health every 10-30 seconds makes a huge difference. To illustrate: A boss fight might last a little while (especially in the early game) with both your hero and the boss slamming each other with attacks. Unfortunately, he's wearing your health down just a bit more than you are -- even with good blocking, he's slowly gaining ground. The only way you'll win the fight is if he drops a random health pickup. The same fight with a self-heal is dramatically different. Hitting Bionic Shielding every 15-20 seconds makes him pretty trivial; his attacks aren't that strong, and your health bounces back up to full or near-full every time you heal. It's just a matter of wearing him down.
Blocking makes this even more significant. When a hero is blocking, he has three to five times the damage resistance he normally has. If you're getting beat down by a group of enemies, blocking and waiting for your heals to recharge multiplies their effects.
Even in PvP, it's incredibly hard to spike someone so badly that they die instantly. Coordinated team spikes work in Stronghold, of course, and spiking a person in BASH or Zombie Apocalypse who has already been wounded is par for the course. Many dueling builds focus on healing debuffs to reduce the power of heals, because normal damage dealing can't kill a player before he or she can react.
Some of the weaker heals, such as Summon Shadows (with Devouring Darkness) and Ego Sprites (with Slave Mentality) get used often, even though their healing is not amazing. They are attacks at the heart, but they have little heals on the side. These heals are mainly good due to the above factors: they're attacks with utility and they offset some damage, especially in PvE.
However the real value of heals is a combination of things, and the real point to be made is that the heals in CO are just pretty awesome all by themselves. Weaker heals aside, the power heals are amazing. Conviction heals for a moderate amount, but has a six-second recharge and no activation time. Bountiful Chi Resurgence's heal over time is even weaker, but it has the Resurgent Reiki advantage to heal you every time you dodge (which, for dodge-based heroes, is incredibly often). It can even stack multiple times.
Bionic Shielding leads the pack; it's the most effective self-healing power in the game. It can heal nearly 3000 HP at rank 3, and has a cooldown (of sorts) of a mere 15 seconds. A level 40 character has around 4500 to 11000 HP, so Bionic Shielding is sort of ridiculous.
If you combine multiple heals, you can really ramp up your survivability by double, triple, or even more. Lightning Reflexes with Bountiful Chi Resurgence can heal rapidly, and adding Conviction or Bionic Shielding can make even an unlucky dodge streak easily recoverable. This isn't restricted to dodge builds, though. A Defiance tank with Support Drones and Bionic Shielding heals incredibly quickly and is almost impossible to break.
This is the main reason why I consider Regeneration a crutch -- other defensive passives provide damage reduction, which multiplies the effect of heals. Defiance cuts incoming damage in half (or even more), which doubles the effect of heals. Regeneration's 300ish HP per second is nice, but Bionic Shielding is almost as effective (that's a pretty significant imbalance) and can be layered with Defiance and dodge gear to make every hit point worth 2.5 times as much as a Regen's. Sadly, blocking doesn't help; the Regen benefits the same amount from blocking as a Defiance character. In fact, Regen decays quickly while blocking, making its healing less effective.
In conclusion, healing is a critical element of Champions Online. All freeform characters should have a heal; even the targeted ally heals are wonderful, although they take a little longer to work their magic. Honestly, I feel that Archetype characters should all have, at the very least, a Conviction-equivalent. Playing an Archetype isn't much like playing "real" CO (and maybe I'm a bit biased here), and self-healing is the biggest reason why.
When he's not touring the streets of Millennium City or rolling mooks in Vibora Bay, Patrick Mackey goes Behind the Mask to bring you the nitty-gritty of the superhero world every Thursday. Whether it's expert analysis of Champions Online's game mechanics or his chronicled hatred of roleplaying vampires, Patrick holds nothing back.
