Sorry for misrepresenting the cost of Antei. It has been a while since I used it and I didn't have nodeka open at the time to look it up. I must have had much smaller pools back when I used it because I remembered it taking large chunks of my endurance. My bad.
Per your argument about casters being more dependent on spells that is true, but if, as Fenulia said, the evasion penalty is max vs max, casters suffer no penalty for being at 20% mana/spirit. Everyone suffers a penalty for being at 20% endurance (which affects hitters much more).
About something adding 50% for 10 seconds... is that really a skill that is all that powerful? If you have something that doubles your damage for 20 seconds though? Look at the costs for using Insanity/Havoc for barbs.
But if you look at the really powerful ones (probably the 3 biggest that come to my mind right away are bleed, forge, battle learning), those are basically bending your opponent over a barrel and having your way with them. You take away your opponents ability to do more than stand there and die. Forge and battle learning require a battle lock which both classes have. Bleed takes away fleeing by simply removing endurance as well as all skills/spells and giving -25% hit/dam.
With the ability to ascend now, how are we really going to be able to differentiate sub-classes moving forward? Personally, I would like to see most new skills going to specific sub-classes instead of going to the base classes. With that though, would likely be more powerful "defining" skills for the sub-class. That results in problems when people can have 2 and 3 of those at a time. Putting them all on the same prevent is counter to the whole idea of having multiple sub-classes. Having a big cost associated with them means that you have to choose to use them wisely as it weakens you in the immediate future and you may not be able to use your other big skill right away.
Maybe part of the overall solution to what I am suggesting is not to add a bonus/penalty for mana/spirit like there is for endurance, but to remove the endurance bonus/penalty structure. That does make it a bit more palatable to have skills that really drain you. Then at least you aren't helpless unless you actually run out.
It may seem like I am just bitching. In a way yes. In a way no. People have been bitching about bleed for years. Casters have been bitching about forge for a long time. In a convoluted way, I would like to see all of the classes have some really cool and powerful skills/spells. But I would like to see them have a steep cost to use. You can nuke the crap outa someone (or make yourself invincible or whatever), but you better hope it does the job, because it using that much power drains you and leaves you vulnerable.
It would add a whole new aspect to combat when you have 2 skills that cost 40-60% 3 that cost 15-30% and 5 that cost 5-10%. But you also have penalties associated with pool loss that you have to take into account (maybe) and still be able to maintain your regular staple of skills. The fact that casters rely on pools more than hitters should be taken into account so as not to drain them as quickly or to give their skills more power (as caster spammables are generally more powerful than hitter spammables).
I think it would add a whole new level of strategy to PvP. Even more so to big battles where things would become very strategic. One person who is very powerful could burn themselves out and become a sitting duck if they aren't smart.
In the short run, yes, it is picking on a select few. In the long run, I would really like to see it as part of a system that affects everyone. All of the (sub) classes would have skills that vary from the the staple of average buff/spammable to several of the somewhat strong (burst type, 50% for 10 seconds
) 5-10% cost, to a few of the strong 15-30% cost, and 1-2 40-60% cost skills.
You can't tell me that doesn't at least sound intriguing.