Let's assume that a team member is counting on me to heal them and I keep getting frozen/stunned/knocked back when I try to, the Tracker tells them 'during this period no healing happened'. The Combat Log parser often tells them WHY no healing happened.
One question though. Couldn't they just ask the healer? Like, I'm fighting the boss; the boss does some mechanic that brings me to low hp; I see that I'm at low hp and expect a heal; the heal doesn't come, I die and the raid wipes. I then ask the healer why the heal didn't come (assuming that I did everything correct and the boss mechanic wasn't avoidable at that particular moment). Healer just tells me that he was CCd.
I played a solo healer for a 36member raid a few times back in L2. The mechanics themselves weren't too complex, but because L2 didn't have any raid addons (or at least I've never used/seen them) - I had to know the voices of players in different groups so that I could heal individual players correctly (L2 didn't have raid-wide heals) and I needed to know mechanics to know when I'd be needed the most.
Theoretically, if it's not the very first attempt at the boss, you'd know the potential mechanics of said boss and would know which ones are the most dangerous ones (at least that'd be my expectations for the raid, if I was a RL). So if the raid wipes due to one member dying after a particular mechanic, I'd assume it shouldn't have taken up too much of healer's "ram" to remember that he was CCd during the last mechanic and that was the reason for the wipe. So he'd be able to answer my question w/o much trouble and w/o either side needing a tracker.
Maybe in some games it's that straightforward.
But if the reason is that the Healer had to heal the Summoner because a Summon fell at the wrong time, and they took an extra hit before they could resummon it due to ability cooldowns, and in that time the boss used a CC ability on the DPS which needed to be cleansed afterward. Then you the Tank took a decent hit but the big heal wasn't off cooldown yet so you used your own, at which point the Healer didn't need to heal you right away, and could prioritize other (originally) less injured party members and finally get around to dealing with the extra Poison effect from the boss that was busy ticking while they were saving the Summoner from a cooldown issue.
Five minutes later when you finally reach the end of the fight, win or lose, the question you the Tank are wondering isn't "Why couldn't you heal me, so we wiped just now?". It's "Why was it so hard to keep my MP up in the last half?"
You don't remember the missing healing, because rhythms shift, and because it's natural to sometimes have to heal yourself.
The summoner never associated them taking that hit with you spending MP in the first place.
The boss just happened to use Poison Aura more often today.
And you, at the end, don't even remember that extra healing beat or two that fell on you, because you were focused on the actual fight for the next 3-4 minutes before things finally broke down, and that self-healing requirement is
normal
, it just came up a few times too often.
In the end, the ANSWER, wasn't even any of that. The Bard missed an ability speed buff on the Summoner because someone's positioning was a bit off, and the Summoner eventually got unlucky as a result (and maybe that happened twice).
Who do you even ask?
There's not much reason you would remember those specific extra self-heals.
The Healer doesn't know for sure why the Summoner got hit.
The Summoner feels like it was just bad luck on timing.
The Bard didn't notice that the Summoner got knocked back while they were singing the "Speed Boost" buff that was supposed to have fixed the timing.
And the Boss may have even used more abilities later on that also made you spend more MP, as a red herring.
Literally no-one even knows, and those who do don't remember, because to NOBODY was their part of this chain of events more than 10% of what they had to focus on in fight as a whole.
But you could ask a tracker:
Tank: "Where'd my MP go?"
Tracker: "You self-healed more frequently than usual during this period."
Healer: "Then how much was I healing at that point, and who?"
Tracker: "You healed the Summoner 5 times in that part of the fight."
Healer: "Hm. Odd. I should only have needed to heal them two times."
Summoner: "Why'd I have so much trouble getting that summon off? Was the boss just extra lucky today?"
Tracker: "You only managed to heal each summon 3 times today instead of 4, due to cooldowns."
Summoner: "Wait, that's not right, why was I slower than ususal?"
Bard: "Hm? I sang the usual things."
Tracker: "The Summoner was out of range for the third recast of Speed Boost."
Party, after all of this: "Oh."
Summoner: "Well that sucks. I'll watch for that and call out if I get caught by cooldowns again."
Bard: "Hm. Okay, then that means I probably need to stand over here instead, even though I'm more likely to get hurt."
Healer: "I can afford to heal you at that POINT in the fight. The problem only comes up later on, after you're done with your buffing."
Tank: "Okay, cool. I won't fix it, cause it ain't broke, and I'd only end up making things worse."
A difference of perspective.
Maybe Ashes will be simplistic. "You wipe right away." instead of "This problem cost you some of your ability to adapt, and you didn't have enough left later on."
If every mistake instantly ends the raid, rather than demanding adaptation and allowing the opportunity to recover through skill, resources, or luck, I'm going to be a bit disappointed.