Quite a few things to answer. I'll split answers to Tevoli and rerp
What do you want to say with all these pet references? Of course pets are broken... they even were pre-AoV where an Elder lvl1 or WW lvl1 suddenly made it possible for every class to solo Goblin Leader for Oridecon and rendered Priests quite useless in raids, if multiple WWs were stacked.
Would I call that a "positive thing" that should be achieved with skills as well.... nope! If a pet defines your DPS by most parts (see crecentia, etc.) we don't need classes anymore and we could transform ragnarok into some sort of Pokémon.
It's safe to say that no Priest want to see these kind of requirements in the party chat or menu: LF FS Priest with lvl4 DOT pet or LF DPS Priest with healing pet.
There was a time where you could replace DoT pet with "30sec Embus" in your statement. Do I want that one back? - Not at all.
But beside of that. Yes, I really wish I could return to the old raids, where you would look for a good (defense-oriented) tank, a couple of FS healers and some decent DPS. And if I could, I would also remove all the pets from RO2, because they started to make stats, skill builds, cards, titles, etc. more or less irrelevant. A WillowWorker was more important for a knight than focussing on defense.
Will it scares potential players away when the game made every class not overly dependent on each others?
I could say quite the contrary is the case. There were more players playing the game when raids were extremely hard and dedicated classes very common. See, if you want to play a DPS class like a Rogue or Sin, you will be proud of your damage output and focus on that. Do I need that class do be able to take up the healer role or tank role as well? Not at all.
And - as I've written - that's the case in so many other games as well... and many of them are much more successful as RO2 as well.
If I play a Rogue in Dragon Age, Dungeons-&-Dragons, Titan Quest, Dark Souls or Skyrim, I accept that I am quite squishy. Does it "scared" players that such a Rogue can't just use different skills / powers / talents to be a tanky class or a powerful group healer as well?
Dark Souls was so popular BECAUSE you couldn't be good at everything, because you have to dedicate yourself to a certain role and BECAUSE the quests were soo hard.
Sorcerer has been doing Hybrid since day one. How many Sorcerer in the game that weren't Hybrid (FS+DPS) ?
That's quite a personal experience. I knew quite a few Sorcerers who played strictly FS as well... and I also knew a lot that turned out to haven't leveled Deluge or maxed LoR and called themself "Hybrid".
And - as I've already written as well - Hybrid had a different meaning back then. It meant - half a healer, half a DPS ... and not "full support AND full DPS depending on the current situation" as it is right now.
So where is this urgent to call out Priest for doing Hybrid coming from? Let's be honest here. PVP?
IMO also wrong. In WoE, the damage output of a Soulmaker is rather kind of low. But the Cure makes him still one of the best-to-have classes around there and are usually quite a high-priority target.
The current Priest on contrast is considered OP by most people BECAUSE he can DoT players in WoE while running around and being able to outheal anything but purely aggressive attacks.
Grind, PVP, Hybrid (Grind+PVP) are the real builds.
So it wasn't because of no clear distinction between FS and DPS for Priest here. It was no clear distinction between Grind and PVP. Every Priest in the game was indeed Hybrid, not FS+DPS, but Grind+PVP. With or without the 20 skill points.
IMO also wrong. I could either play my Priest as either DPS in a grinding party (using ME+Oratio a lot), as a Hybrid (stunning + healing) or as a full support.
So the amount of grinding isn't such a defining factor for a mixture of roles. However, the post-AoV inbalances made it all too easy to just level Renovatio and Cure and call yourself "Full Support".