Leiron, civilpaw
I know developers can and do underestimate their clients all the time, but I don't think that's what happened here. Take what they've said.
First, we know that the original statement on coil was that it was very difficult, so much so that he doubted 100 players would even clear it all by the time 2.1 came out.
Next we get the WAR complaints. Yoshi responds by saying that WAR is very strong, the devs prefer WAR, and the players need to do more research. It's important to note that part of his *proof* that WARs are strong is that most of the devs prefer them, and this is not hard for me to believe. Think about it, they already know all the fight mechanics. So they don't have to really worry about learning an encounter or reacting to much since they know how it's going to go. They're also playing with the same people over and over again. This really limits the factors outside of the class that can make a fight interesting. So it makes a certain degree of sense that they'd gravitate toward the tank that was a little more involved since class execution is really the only thing they have to worry about.
Anyhow, if you believe that devs are preferential to WAR, the next thing is they're continuing to insist that WAR is very strong. It's the confidence of this statement that strikes me. It says to me they've probably done all the content everybody is complaining about as WAR, likely even double WAR since they're so certain about WAR viability. Now we all know coil with a WAR tank is a little more difficult for the raid as a whole. You have less room for error. So if they have completed all content with WAR, and especially if they've done it with double WAR, it stands to reason they've played around with the class in coil a fair bit.
Then we get the retraction (of sorts, it's not really a retraction since they never state WAR wasn't functioning as intended). Yoshi says PLD is unintentionally making certain encounters less difficult than originally intended, they don't want to nerf PLD and make people unhappy, so they're just going to buff WAR. The thing about the PLD is it's VERY straightforward. You have one combo that does both debuffing and threat generation. Their cooldowns are really simple, press button and take less damage (or no damage). There is nothing complex here. There is none of the trade offs for skills to worry about (hold wrath vs. use inner beast for instance), there is no interplay between skills that change their effectiveness (ie: berserk to boost inner beast and/or bloodbath). So the idea that they didn't anticipate the PLD using his abilities to take less damage to ... take less damage is difficult to believe if they were playing that class much.
So, they very likely played a lot of WAR in coil since they're so insistent that WAR is viable in coil. And they didn't seem to play much PLD in coil since they somehow underestimated PLDs extraordinarily straightforward ability set. So I think it's very possible that when designing and testing coil, they did so with the class that they preferred to play (WAR). And didn't put so much effort into testing out the other class (PLD). They just did enough to make sure the PLD could also do the content, but didn't really stress test it.
And thus, it seems most likely that 2x WAR got a lot of playtime for the devs in coil, and PLD parties didn't get so much. This is further enforced by their original statements about coil difficulty. Running a double WAR setup matches up with what they originally said about how difficult coil was going to be. So it's safe to say that, for all intents and purposes, coil was designed with double WAR in mind. PLD party variants (particularly 2xPLD) turned out easier than expected since they weren't tested as much.
If this was the case (and it seems very likely to me), then calling raids with WAR tanks "normal mode" is appropriate. All it means is that's about the difficulty that was originally intended. And you can call raids with PLD tanks "easy mode" since they are able to make the experience easier than intended.
So.... grats to the guys in the video for completing the content on what's safe to assume is the originally intended difficulty.