I must disagree,
Tanks are already in short supply in any MMO.
Hell, I’ll use FFXIV as an example for this.
You can dungeon your way pretty much from 15-60. Tanks (because of their minuscule numbers) get queues instantly. Sure, in a game like this, being stuck needing to party as a tank is fine.
Tanks have the means to cap quickly and efficiently, faster than both DPS and Healers.
Now, ToS, the first dungeon was what…50? My memory is fuzzy but the next one was something close to 100, right?
Thing is, in a game like this, you’re better off taking a Swordsman that dipped their toes into Peltasta for Swash buckle and went something else for damage.
Now, this type of build still works for tanking, currently (as far as we know) but this may not suffice for dungeons as we go higher up. I would say Stat resets are more of a commodity if tanks can effectively and optimally build that way and still be able to tank whatever endgame content there is at whatever the cap is.
If not, then resets need to be a thing. Grind parties can be quite fickle, especially if another play can offer the same asset a pure tank can (Swash buckle) on top of more damage.
Also, I don’t think it would bring any issue at all. Regardless of whether or not someone just changed stats to tank and has not tanked a single dungeon in their ToS career, they will still need to just learn the fight for the instance.
Just as a DPS needs to, just as a Healer needs to. From my past experiences in FFXIV, the endgame tanking in it was simple. Much easier than being a DPS. Purely Tanking endgame dungeons can only be so difficult, after all. And I doubt entry level content is going to be a strain for someone that has just capped. At this time though, we’re just playing with theoretical information.
All I am saying is it wouldn’t be wise to force the necessity for a Pure Tank and then punish said Pure Tanks while they level with no stat resets.
It may work out fine at first, where people are looking for parties but populations diminish in games; it happens all the time. What happens when the Pure Tank can’t find anyone to party with? Then we fall into an even worse version of the common Trinity system issue.
No one plays a tank.