General

F/P don't really seem fun. They seem like people force themselves to play them because they have mage equips or they want a mage with high damage.

Definitely F/P
Sairs are really squishy at higher levels, makes it boring to level

I'd go corsair personally
But Corsairs are squishy and imo mages have a tad bit better survivability and mobility w/ Magic Guard & Teleport
Up to you since you already have a F/P, play it after RED and see if Corsair is better etc

Sairs are extremely easy to use and fun! F/P's are a little more complicated IMO and also not near as fun also IMO. It seems to be that F/P's get the shorter end of the stick from RED's revamp where as Corsairs get a great revamp! I generally find Corsairs much more mobile and easy going, my playing preference also comes into role whereas I pretty much only like NL's. However, NL's are to expensive to fund, Corsairs is a cheap alternative to NL's considering that they're both ranged and have decent damage with very little funding, they both have extremely low hp.