true, totaly forgot about archers xD
but i’m talking more about swordsman, its hard for other swordsman classes go evasion, even with +18% from guardian
Its simple, need more survivability against mages? get con, more survivability against melee/archers? get dex. You got to find what the perfect balance is for you. You can even get a set of plate armor to use vs mages.
More survivalability vs archers get dex? Hahaha, you really know your stuff don’t you 
If you’re going Rodelero C3 then you should Pick up Rodelero at R4 when its normally available. Rodelero isn’t a tank class anyways (hell neither is Fencer), they’ve got tools that you can use for defense (so does Highlander via Crown, Crossguard & wagonwheel/Carter CC’s…).
Tanking is about
Getting aggro and maintaining aggro.
A dead person cannot hold aggro (just as dead dps deal no dps) so tools to survive help you do your role. Direct Aggro tools are Provoke (swordsman c1) and Swashbuckling. Provoke scales off damage which means the more damage you deal the better you are at holding aggro. This means you want enough damage to hold aggro and enough defense to not die (as you cannot hold aggro when dead) as far as the main purpose of tanking goes, Only Peltasta (and Swordsman c1) actually provide tools directly related to being a tank.
Slithering helps you not die against magic, which is why tanks value it, CC also helps you not die (monsters can’t attack while stunned).
Rodelero C3 gives you High Kick which is a skill to boost Strike damage on a target and is basically a party dps boost for strike damage dealers. The only thing that has to do with tanking is that more damage = more threat.
Dragoons is a better individual damage dealer then Rod C3 though so you might as well picked Dragoon if you just wanted more threat at rank 7.