Your definition seems too specific to me. IMO it's better to have simple rule for broader concept (immunity) and have exceptions in special rule (attack trait) than to have specific rule for broader concept to avoid exceptions now.
The problem is we want immunity to prevent the object from being affected by such spells, regardless of if they can be targeted, so any such spells, effects, or conditions that are meant to affect them will need an exception written. We don't just want attacks to deal no damage, we want them to have no effect at all. No burns, corrodes, pushes, slams, weaks, etc. There's no way to write a rule that prevents these things but doesn't prevent other effects without specific exceptions written.
So, if we need to write exceptions anyways for them to have an effect, I don't think we need to change the rules to allow them to be targeted without an exception.
OK, good points, let's take it from there and see if we can come up with an Immunity definition that is simple enough to easily remember and which allows you to target an immune object.
So:
- You may target a "type" immune object with spells and attacks of that "type"
but :
-
Attacks MAY be avoided ( during step two of the attack sequence, where "immunity" also beats "unavoidable" ) meaning no combat dice and condition dice are rolled ( = mission accomplished ) but additional
non-dice rolling effects - written at the end of the attack bar - may still apply if possible
ex. Extinguish, Defrost still have an effect
ex. +2 vs non-living or pierce+1 obviously have no effect anymore
-
Spells MAY be countered during the counter spell step or upon being revealed.
By giving players the choice to either avoid attacks or not and counter spells or not ( to which the object is immune of course ) you still get the same results as with the current official ruling but now you have the added ability to let the attack or spell pass if it is beneficial to you.
This way it would be possible to play a face down Poison Blood on a Necromancer - to check for a Nullify for instance - but it could be countered and destroyed upon revealing it. If not countered at that moment the spell would resolve
and take effect.
It would also be possible to play a beneficial spell like [mwcard=FWE02] Circle of Fire[/mwcard] on your [mwcard=MW1C16] Flaming Hellion[/mwcard], decide to NOT counter it and let it work normally ( Thanks Jacksmack for the hint : see Jacksmack's post below ) which simply makes sense.
Other interesting note to point out :
Since an attack spell is a spell and also an attack you would have the possibility to counter that spell during the "counter spell step" of the Spell sequence but it would also be possible to let the spell resolve and then "avoid" the attack but benefit from any "non dice rolling effects".
ex. Your [mwcard=DNC20] Vine Snapper[/mwcard] has 3 Burn counters on him which you want to remove.
You Target the Snapper with [mwcard=MWSTX1CKA01] Surging Wave[/mwcard]
Since the Snapper is Immune to Hydro Spells you have the option of Countering your own spell during the "counter spell" step, which you obviously don't do.
The spell resolves and now the Snapper is attacked with a Hydro attack and since he's immune to those you now decide to "avoid" that attack during the "avoid" step of the battle sequence.
No dice and no condition dice is rolled but Extinguish still takes effect and the Burn counters are removed while your Snapper takes no damage at all.
Logical, short, not difficult to remember, mission accomplished so far imo.
What we're doing here is basically taking a situation where the game tells you that you
can't do something while leaving the player
no choice at all and turning it into a situation where the game tells you that you
can do something and gives the players
choices to make with that.
I think we will all agree that the latter situation is what gamers prefer most.