If all you do is press swashbuckling and then C you’re playing incorrectly.
This is an action based game where the majority of attacks are evadable by positioning or jumping.
Since most attacks are evadable, positioning is the first method of defense, most classes will do this from kiting or standing in the backline. For classes that can actively block (Rodelero, Highlander, and Peltasta) this means they can time their Block to when an enemy is attacking them.
Aggro is built through damage and as a result you should be doing damage whenever you can as a tank, and blocking solely to prevent fatal amounts of damage.
Since Peltasta and Highlander both Block (Cross Guard for Highlander and C guard for Peltasta) this means 2/3rd of your options at Rank 2 can block physical damage. Swordsman 2 is a feeder to Swordsman 3 which also cannot block but which naturally progresses into either Cataphract (Has synergy with Restrains Slow and Steed charge, but otherwise the two do not mix well) or Rodelero (which can block).
Pretty much the only Swordsman builds which cannot actively block already are
a) Swordsman C3 - Cataphract builds
b) Swordsman C2 - Hoplite
c) Swordsman C2 - Barbarian.
These are not anomalies as hoplite utilizes 1h skills allowing passive block through a shield, and Barbarian has no weapon type demanded also allowing passive block through a shield.
Swordsman C3 - Cataphract gives up the ability to block for sticking power via Restrains Slow and Trots speed. This is a mobile set-up that is difficult to escape and has synergy between the Slow and Steed Charge getting guaranteed crit. Naturally this is more relevant to potential PvP purpose then PvE.
Even for those without active Block (C2 swordsman into Barb/Hop), the Fencer class prides itself on evades and gains damage for not using a shield anyways which provides another alternative to blocking for the frontline class type. Meaning Swordsman has covered Blocking (Highlander, Peltasta, Rodelero), Mobility (Cataphract and Dashing) as well as evasion (Fencer and Peltasta).
There are already solid defensive options for those tanking and those who are not tanking.
Dedicated dps (normally) would avoid a skill like Swashbuckling because focusing a large amount of targets on yourself as a dps is dangerous whether you are melee or not.
Taking an aggro skill to “be a desired dps” is almost an oxymoron. Slapping a dedicated aggro skill onto every Swordsman class by putting it in R1 is ridiculous and counter-productive for anyone who wants to actually play dps swordsman as you are permanently cementing the entire class tree as tank based. The reality is that dedicated DPS shouldn’t be able to survive pulling with Swashbuckling and instead being worthwhile for their own damage contributions.
Squire and Corsair are both party focused character types in R5 and serve as natural exits to Peltasta and Highlander. There is more then a fair chance that r8 will include new defensive or party focused classes (centurion???) for support focused Swordsmen, however the other class circles are about damage and their validity as damage is whats important, not their ability to be a punching back for 4 other people.
tl;dr.
you’re just muddying the waters with bad suggestions.

