Having more HP is not always the solution anymore.
Rank 8 mobs hit so hard that as soon as you hit that swash buckling button, it doesn’t matter if you have 30k hp or 60k hp, you’ll still die in a couple seconds.
Hell, I have a full CON kabbalist 1 that can reach 100k hp with Ein Sof and he can’t tank stuff without pulling everything with swash buckling.
The thing is, Pelt 3 Squire 3 is trying too hard to be the “old school” tanker. It might work well until rank 7, but at rank 8 you’ll start facing some big problems.
And It’s not just a matter of tanking stuff, it’s now also a matter of keeping stuff aggro’ing you as well. When mobs start getting 300k hp, the provoke you get from Swash Buckling doesn’t cut it anymore. You can imagine Swash Buckling’s provoke as a static value as if you dealt 100k damage to every mob around you. Now when mobs get 300k hp and you can’t keep up with other rank 8 dps, other party members will naturally steal the aggro from what you’re trying to tank.
For the above mentioned reasons, people are now seeking other methods of mitigating damage and keeping aggro. Skills like Restrain will provide CC so that mobs don’t hit you and make the whole tanking life easier. Slithering provides magic damage immunity during 10 seconds so you can tank stuff right after using Swash Buckling, but remember, you might lose the aggro during those 10 seconds if you just keep Slithering.
Now, regarding DEX and evasion, I’m never building a full CON character anymore that’s not 100% pvp oriented. That squire build probably would go full CON, but DEX brings so much more benefits that I don’t even know where to begin with. A mix of DEX/CON works a lot better in any pvm tank due to evasion and the fact DEX also gives you some dps.
“Tanks” are in a very weird place right now. It’s much easier to CC stuff or become invencible through a skill than try to mitigate monsters damage through sheer amount of hp.