I guess that's a very broad way to describe it. Simplifying things even further, "power" and "attack" have the same function, we could probably just call them "round-winner..." Likewise, "damage" and "life" have the same function, so we could probably call them "gap."

However, these pillars are too basic to give any idea of what a card's *role* actually is. Roles are more complex and can combine the functions of multiple pillars, or apply them in indirect ways.
Some examples of roles:

Wall: This card is difficult to beat. Its typical role is to deny damage indirectly, either by forcing pills, or by beating an opposing card for low pill cost. EX: Chiara, Mona, etc.
Threat: This card combines average or better round winning power with average or better gap. It is usually too ambiguous to easily read, as it is not too high-impact to bluff, but too high-impact for your opponent to let it through without consequence. EX: Murray, Dagg, Pan, etc.
Nuke: This card gaps extremely well. 4 or 5* nukes sometimes have above average round-winning power as well. 4 or 5* nukes that lack additional round-winning power usually gap for hilariously high amounts. EX: Ongh, Eddie, Greem, Karrion, etc.
Dual purpose: (For lack of a better name) This flexible card combines some form of DR/defeat ability with decent gap. Because of this, it can play multiple roles against most hands. Ex: Marina, Kusuri, Lady.

There are other roles -- Mitigating, Fork, etc... not enough space to describe each one.

"As a card concept creator"

You mean you design UR cards or what?

I think it can be reduced to three things ultimately:

1 - Relative attack
2 - Relative damage
3 - Nullifiers and anti-nullifiers

Attack is needed to deliver damage, but given enough damage card can reduce the need to compete in attack - Kolos is example of this. It has mediocre attack capability of card - but that is offset by damage high enough to make the game in one hit.

Pillz are essentially most part "attack" but also a little "damage" due fury factor - either by removing fury options from opponent or gaining those options to yourself as form of extra pills. Pillz-related attack is not for this card, but the cards following it, thus it needs to be evaluated by overall deck power to see how effective pillgains/loses is.

DR is actually as much "attack" feature as it is "damage" feature - this is because when you can DR damage you dont have to wall it with attack. DR is offset by -life ablities that are one form of relative damage that counters the DR-benefit.

Nullifiers mean SoA and SoB - They cause disruption of any related feature from target card, therefore nullifiers are targeted against all abilities/bonuses on the field and they have "generalized" effect, they are a factor when deciding for card worth as having nullifer (Jackie) or being nullified (fex. Copper). anti-Nullifiers are antitheses for nullifiers (stop: abilities and protect bonuses). Nullifers must be measured against whole metagame to see how much they are worth on average.

@Frowns
No, he makes ideas that could be UR cards if they weren't freakishly overpowered or underpowered but most likely won't be unless the lightining strikes something and by coincidence something like a 7/2 Sob goes through for the Pussycats.

I've been working on a stats value system for a Fantasy Rivals database. It makes more sense releasing it for FR first, as it will feature less characters and is easier to adjust than UR.

I divided stats into 5 main categories:

Attack: Attack and power modifiers
Damage: Damage dealing or life reducers.
Defense: Damare reducers and heals
Manipulation: Pillz, sob, soa...
Level: simply, star count.

This doesn't help a lot in card design, but is a visual help when comparing characters and finding their strengths and weakneses.

Also, I put stars in there due to their importance in deck building. In FR you can't simply put together a 40 star deck.