My first bit of advice would be to not pump Dex so hard. You will get to endgame and have a crit rate of probably 30-40% depending on gear. That is pretty nice, but your physical attack might be a bit low.
Let’s say you go highlander route end game, you will get the + crit damage so you will gain +110 damage from strength on non crits, and + 330 on critical attacks. Let’s compare this to going 3 Str 1 dex instead. You will lose a lot of crit rate, obviously. Your crit rate will be down to around 20% , again depending on gear. However, you will gain around 330 damage on standard attack and a whopping 990 damage on crits.
This doesn’t take into account the extra 50% damage you get when a skill crits which is of course massive, but as you can see, from a purely damage standpoint, higher strength is typically more reliable. That’s because that is the only thing Strength is good for. You will lose out on evasion and accuracy of course, but evasion isn’t exactly amazing late game, due to how strong magic is, and accuracy isn’t really needed in PvE like…at all. In PvP you may struggle to hit Dex builds.
If your main goal is to just critical all the time, by all means proceed, but at that rate you almost definitely want to go Barbarian. The reason behind this is that, at least until they change it to the buffs Korea is getting, Cleave gives +50% crit rate. That’ll give you a really nice crit rate. If/when it does change, it will make the enemies vulnerable to slash damage, which is still amazing and a wonderful buff.
As for throwing Corsair, I wouldn’t particularly recommend it for your builds. If you’re going 2handed sword it really only has 2 things to offer you: Iron Hook for PvP (which is amazing but hard to land) and Jolly Roger for PvE (which is a decent buff to be sure, but it is highly situational, aside from the gold which is always welcomed). Most of Corsair’s potential is locked into circle 2, which makes them fairly unique in this case.
I hope this helps you decide a bit.