Hey Krk and welcome... back! ^.^
I'd like to start off with a reminder to take a look at forums rules with language ;p I'm sure it wouldn't offend anyone around here but the GM's can't be too careful and will have to remove it or close the thread regardless.
On to your questions,
I personally play the Indigo PVP server, along with Artemis a PVE server, however there is also the server Grimdal which is PVP, both of these servers have low numbers, for what reason I can not be sure... However both also have fantastic people to mess around and chat with. That being said, endgame content on these servers is harder to reach then on a PVE server, but honestly playing both a PVE and PVP server, I can say it's much more rewarding and fulfilling to complete a run on Indigo ^.^
This game is what I would classify as P2W yes. However, it IS becoming increasingly easier to be F2W aswell, just with or effort put in of course.
As for combo's in game, for PvE and PvP... There are still semi-'useless' classes, BUT they have also been able to balance out quite a few classes in order to have a selection of different classes to play successfully, rather having to select a certain class or be killed.
If you have anyother questions or require further details on the above answered just let me know via a forum PM, response on this thread, or you can PM me in-game on Indigo, most likely being able to find me on characters Zencast or Shannondoa.
Goodluck, and happy hunting! ;D