so that brings up another question: how or where are champs put into categories like "damage dealer" or "debuffer" or "healer". Champs have a diverse set of skills, so how to you place a category on them? I am familiar with the categories of attack, defense, support, and HP. I have seen those other words used but not knowing of any list of such info.
My warmaiden has 61% CR, 75% CD, 194 ACC which if any of those should I tinker with? Personally I would call her an Attack champ.
The champs are not labeled as damage dealer, debuffer or healer in the game. But a lot of categories are still quite obvious.
A healer is a champ that can heal your teammembers. Read the skill description to get to know. For example High Elves epic Thenasil, his A2 skill: Places a 60% [Increase DEF] buff on all allies for 2 turns. Heals all allies by 25% of this Champion’s MAX HP. His job is to heal your teammembers. Crit rate and crit damage don't help to do so. The heal is based on his max hp, 25% of his hp is the ammount of healing, as you can read in the skill description. Thenasil with 10k hp heals for 2.5k hp, Thenasil with 60k hp heals for 15k hp. This champ gets better, the higher his own hp is. You want a lot of speed on Thenasil as well, so he can use his healing ability more often during the fight.
A debuffer is a champ who can put debuffs on your enemies. Warmaiden can put decrease def on all enemies, she is the best example for a debuffer. She needs enough accuracy to land her debuffs. You can increase her damage in addition to that, but that's secondary. If she doesn't land her debuffs, she is useless.
A damage dealer is a champ with high base stat of his damage increasing stat (for most champs attack) and high damage multipliers. Like kramaswamy allready said, you can find the damage multipliers on sites about the game like Ayumi. There you can see that Warmaiden has a damage multiplier of 4 on her A3 skill, her base attack is 1321. That results in a base damage of 1321 x 4 = 5284. That's ok, but not overwhelming. I would not consider her as a damage dealer.
Compare to, for example, Trunda, the best damage dealer in the game. Trunda has a base attack of 1608, her A3 has a damage multiplier of 3 and can hit twice. Base damage of that skill is 1608 x 3 x 2 = 9648.
Calculating the base damage of a skill is a good first step to see if your champ can work as damage dealer. There are other factors as well, special abilities of a skill like ignoring defense (Royal Huntsman), allways critical (Ithos) or stuff like that.
Let's go back to Thenasil, is he a damage dealer? His A3 can attack all enemies, and it has a quite high damage multiplier of 4. But his base attack is so low, only 991. So the base damage of his A3 is only 991 x 4 = 3964. Compare that to Trunda's 9648. Obviously Thenasil is not a damage dealer. And he doesn't have to be a damage dealer, he is a healer.