Well mages, warlocks, and any other dps that uses a mage staff or wand get gimped at 75 cap compared to the other dps classes.
They're not gimped by skills (as far as I know anyway), but by the weapons that are currently listed in the database for 75 cap. The level 75 weapons I list below are each the best and highest damage/dps weapons I could find in the database, and are almost certainly the hard mode weapons of the coming level 75 instance.
Here's a comparison of level 70 vs level 75 staffs each at Tier 10 and Tier 11.
70 staff - Shackles of the Curse Face T10/+16/OD = 9634 magic damage, 5232 magic attack
70 staff - Shackles of the Curse Face T11/+16/OD = 10076 magic damage, 5520 magic attack
75 staff - Arbitrator of Fate T10/+16/OD = 10073 magic damage, 7742 magic attack, 883 intelligence
75 staff - Arbitrator of Fate T11/+16/OD = 10535 magic damage, 8078 magic attack, 938 intelligence
This is roughly a 5% increase in damage... and you might notice that a T11 shackles has as much magic damage as a T10 level 75 staff. This happens because every weapon has two ghost stats and weapons that only show one ghost stat (such as the magic attack on the shackles) have a hidden ghost stat that increases damage. But for level 75 staffs and wands they replace the magic damage increase with a intelligence ghost stat. I don't list the wand comparison here, but the numbers scale the same.
Now to compare to rogue daggers.
70 dagger - Shint's Secret Intelligence T10/+16/OD = 5743 physical damage (3173 dps), 3516 physical attack
70 dagger - Shint's Secret Intelligence T11/+16/OD = 6007 physical damage (3319 dps), 3516 physical attack
75 dagger - Dim Light T10/+16/OD = 6989 physical damage (3861 dps), 3873 physical attack
75 dagger - Dim Light T11/+16/OD = 7309 physical damage (4038 dps), 4039 physical attack
The level 75 dagger gets roughly a 20% increase in damage/dps compared to the level 70 dagger. Notice it only has one visible ghost stat, the other ghost stat is a hidden physical damage increase that gets added into the damage total.
I'll list the stats for the two handed axe here too just to drive my point home, but it's the same % increase for crossbows.
70 2H Axe - Lekani's Strength T10/+16/OD = 13260 physical damage (3480 dps), 7032 physical attack
70 2H Axe - Lekani's Strength T11/+16/OD = 13868 physical damage (3640 dps), 7320 physical attack
75 2H Axe - Global Destruction T10/+16/OD = 16029 physical damage (4207 dps), 7747 physical attack
75 2H Axe - Global Destruction T11/+16/OD = 16764 physical damage (4400 dps), 8078 physical attack
Again, roughly a 20% increase in damage/dps. Crossbows see the same scaled increase.
To be thorough I'll mention that Two Handed Hammers do not have a hidden physical damage increase at 75 cap, but neither do their level 70 counterparts. The same applies to both level 70 and level 75 one handed axes... though instead of bonus physical damage they get bonus physical crit rate. Despite the fact that they never had a bonus physical damage increase, both of these weapons at their level 75 incarnations are getting a 20% damage increase compared to their level 70 versions.
I could live with bonus magic crit rate on my mage staff instead of bonus magic damage if that were the change made, but instead they replace the magic damage bonus with intelligence. Intelligence is nice and all... but it'll amount to about 2k magic attack and leaves us with 15% less damage compared to what other classes get. The increase in magic attack is pretty large... but I'd much rather have weapons that do 20% more damage than level 70 weapons than have ~4k more magic attack.
Oh and before people start saying "good, p/s will get a nerf from this at least" or something similar... this will barely affect siege and pvp in general, mostly just PvE. P/S and other magic dps will still hit more than hard enough for every type of pvp as they are now thanks to how pvp works in RoM (one shot or be one shot).
Anyway to wrap it up... I'm kinda pissed about this and am considering trying some other dps class or giving up entirely and not even bothering to retier a staff. I'll admit I've only been playing since chapter 3, but I've never seen anything put in the database as preview of what's coming changed before the new content was finally released. I doubt this will change. I hope it will, but Runewaker makes so many nonsense decisions about content I have some very strong doubts.