I'm afraid I can't agree with you.
I don't think "Angel" could use as an lifesaver spell indeed.
If a DPSer has overed threat, he must to stop creating damage and avoid some damage from enemy.
In most situations, "Angel" couldn't save anybody indeed because of it having no idea to existing threat.
There are some players complaining about "Angel's CD" too.
I'm sure most players would get the same feeling.
"Angel" is a worthless spell for its huge long CD.
Angel allows the target to go full DPS for the duration and not only create no threat, but also increasing the threat for the maintank by that amount. This increases the threat gap between the aggroing person and the crusader by a huge amount and is very useful in a situation where the Crusader is struggling to build up enough aggro.
Also, it allows the sorcerer or Berserker to just pump out that burst damage in the very first seconds of a boss without any danger, making it considerably more easy for the crusader to keep the boss under control.
It can also be used tactically during the fight, to apply huge AoE threat to the crusader if needed by combining it with AoE abilities of other classes.
This spell is
not meant to be used in every single situation or AoE, because that would be ridicolously overpowered.
The long cooldown is justified. I'm perfectly sure a lot of people will sacrifice a spell slot for Angel despite its cooldown.
The same to "Stone Skin".
When you are deep in dangerous also be in low HP usually.
50% dam reduce means double your existing HP now.
Which is huge, considering that damage mitigation is basicly the same as being healed.
I really think it could not save you indeed.
As a lifesaver spell 50% dam reduce effect is too weak to save you indeed. Specially to such a long CD.
60 seconds is not a long CD. Most boss special cooldown abilities have like 30 or 40 seconds cooldown. Having Stone skin ready for action every time a boss uses its special attack would be ridicolous.
I also remember there is a talent for Crusader is:
"When the hitpoints of the Crusader are below 25% of the current maximum,all damage taken is reduced by 50% [applied after armor and resistance rules]."
It also a lifesaver effect, as a passive. Affects all the time and at least added amount to 25% HPs.
But "Stone Skin" isn't. It must be used in correct time, only last 5s, cost 12mana every time and still for waitting 30s CD basing on a telent. But you also couldn't assure it could help you saving amount to atleast 25% HP.
I really disagree this skill now. I hope it should being better.
I think most Gaia's fans would glad to see this change too.
Apples and oranges again. 'Stone Skin' can be controlled, the Crusader talent can not. You can trigger 'Stone Skin' in expectation of high damage, even when at full health if you know the next moments will be rough. Also, the crusader talent is practically useless if you do not have the HP pool to back it up, as attacks that deal high damage with one single strike might end up not being affected at all. Also, when your HP is above 25%, it does absolutely nothing. Also, you can't compare a top-tier talent to an ability. Abilities do not limit you in talent speccing and are always accessable, no matter which talents you have chosen. Talents are only accessable if you select that specific tree, which takes that customization opportunity away.
All in all, the tactical possibilities of 'Stone Skin' compared to the Crusader Talent are huge, as you can trigger it whenever you want. Your healer is busy or too far away to heal? Just Stone-Skin until everything is back under control! Can't evade the next AoE attack? Put up stone-skin and hope your HP will do the job. Pulling an entire group of units at once, all ready to burst out that magic Missile? Stone-skin and rush in! Healer close to get aggro due to a lot of healing? Stone-skin to take 50% of healing threat away.
Again, the cooldown is justified.
Both Stone Skin and Guardian Angel are spells you do not have to take, but are nice to have. If you can control all of the encounters just fine without, you won't need them. However, if you keep wiping on the boss ahead, it might make all the difference.