I would like to see at least 1 skill closely related to time for each class. Some ideas:
Time stop bubble (mage) - Default version stops enemies (and possibly allies) inside. Could transform the skill to stop everything outside instead. Could be modified to give allies various speed buffs which would give the mage a way to help allies in multiplayer.
Echo self (rogue) - Your echo, from a different timeline, appears at your cursor. Pressing the skill again while it is active allows you to take control of your other self. Enemies can be attracted to either self and if you die then you get control of the other one. You can take control of either self as many times as you want while the skill is active (maybe with a 1 second cooldown). They have separate health pools.
Limit the skill with a duration, an increasing life cost, and/or how far you can be from your echo. I like that idea that the longer your echo is in this timeline, the more violatile the situation becomes. Maybe you take more and more damage over time.
The skill could be modified so if you and your echo come close enough, then you both explode leaving behind 1 self that takes 50% of current health as damage.
Call Ancenstors (primalist) - Call upon ancenstors (like Caveman Jim) from an earlier era. They are not minions and instead buff your character. The skill could have 3 paths. The first node in each path would add another ancestor. So you could focus on 1 really good ancestor or multiple ancestors but with less power. It should feel like you are leveling up the ancenstor as you spend more points in that path.
You would also get a 1 time use during the skills duration that would trigger each ancenstor’s special ability. I imagine the ancestors being mostly stationary and remaining where you summoned them.
Shield ancenstor - provides defensive buffs. The special ability would blocks attacks with a big shield.
Drum ancenstor - provides offensive buffs
Shaman ancenstor - provides alternative buffs like mana regen. The special ability would transport your character from you current location to the Shaman. This would give the primalist another movement skill besides leap.
Revive self (acolyte) - Forseeing your own death, you cast a revivfy spell on yourself. If you die within the next few seconds, you are revived as a skeleton archmage. I like the idea that if you time the skill wrong and you don’t die, then you suffer a penalty. But a skill node called Change Fate could turn that penalty into a bonus if you take damage and are able to survive the next few seconds.
Once you are an archmage you retain all your skills and pressing Revive Self skill again would allow you to steal life essence at cost of health. Life essence slows drains and once you run out, then you are dead for good. If you are able to obtain enough life essence without the archmage dying, then you are able to return to your original self.
If you are running low on life essence, then you suffer a damage or speed penalty. But if you have a lot of life essence, then you could temporarily push beyond the power of your mortal body. Carefully balancing your life essence would give you more damage as long as you are careful not to accidently revive your self for good.