This is just for kick’s what if they allowed you to cross over classes to fit your play style almost like unlocking a hidden combo class if you will like say a warrior with a wizard rank of pyro magic or such even soceresses with cleric or tamer skills or the ranger or healing class almost like out of the box experimenting i’m not sure if they’ll allow it in the future but if so what would you be a what would go with what remember it’s for fun so go nut’s. 
I’m fairly sure there was a really old topic about this but I don’t think this is a good idea since it would just lead to people choosing only their favorite classes or the most OP classes and then just stop playing until there is an update when they reach max level and get good equipment.
But isn’t a mmo accustomed to appeal those who should feel free to play how they like but even so it’s fun to imagine XD
No thanks i would like some form of balance in this game. And if they do this they might as well remove classes and just make a massive skill pool. Basically no thanks it would require most of the game to be RE developed.
Ahahahaha you have a a decent point but it’s always good to keep an open mind no an also I wouldn’t like the game to be ruined either. XD
what if they allowed skill upgrade’s that alter a skill into a brand new one at a mastery lvl, would that be interesting or nah ?
I completely agree with @Garrnett and @thebloodyaugust on this, it will be much harder to balance classes when you can choose any class from any tree, and will take away from the fun of making multiple characters 
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To add to your idea though, perhaps as your very last rank (9 I believe?), there could be a hidden quest which will allow you to choose the FIRST (and only the FIRST, anything else would most likely be too OP) rank of any other class tree. IMO doing so would lead to a less powerful build than if you had chosen a rank 9 class in your own tree, but could lead to some interesting builds. Archers classes with the Swordsman’s Bash/Thrust for close-quarters combat (and some buffs to boot), Swordsman with Wizard’s Sleep to use as a gap-closer, or Wizard classes with the Cleric’s heal/safety zone.
Yeah, I get where you’re coming from but it’s just my opinion against it But yeah I can see some people liking that style of class advancement better than the one we have now since it’s hard to decide on which class to main as which just leads to making them all … at least for me
An OP class combination I’m thinking of is Swordsman > Wiz > Hoplite > Chronomancer 
I’d be the tankiest class ever and I think I could stack some INT too because of Hoplite attribute with Finestra, Wiz Reflect Shield is fairly OP IMO and Chronomancer increases attack speed and critical rate 
Maybe even a Thaumaturge for Transpose switching CON with INT so if I want to be tanky, don’t use it and if I wanna do more damage, just use it to get more damage
Right on Chebus, now that’s throw in a plot twist what if they threw in a reborn mechanic but doing so of the main tier class you choose has a a rank 10 awakening class you can choose from hence maybe it’ll open a new sort of playing style maybe i’m just putting idea’s out here we can keep adding on until we get a beta date .