They are far too vague and don't provide the player with anywhere near the information they need.
Case in point Lifegiving veil.
Best used to heal a party or raid.
Damage dealt by the Mage heals up to 5 party or raid members for a small portion of the damage done. Heals significantly more using Life damage. Heals significantly less using area effect damage. Lasts 1h.
Okay great, this tells me absolutely nothing about how much healing will be done by using an ability.
It also doesn't say how far the person needs to be in order to benefit from the effect.
How much more healing is done with life damage?
how much less with AE?
Or another example, Arresting Presence:
Applies Arresting Presence to the target, Silencing all nearby enemies. Consumes Charge while active.
Okay great, but now I have absolutely no idea how close they have to be.
In fact this means that the tooltips for improved presence as well as the nyx dom crystal now make no sense.
How much was the base Arresting/Reflecting presence?
Is it now 15 m?
If it is impossible to toggle between simple tooltips and detailed tooltips, then leave the detailed tooltips.
It is better for someone to be confused and ask for clarification, than for them to be completely ignorant.
You don't do it to DPS/Healing abilities, don't do it to utility based abilities.