Did a little testing of FoK and Crimson Tempest.
1) FoK, at level 85, does 1350 + .48 * AP damage, which matches what you see on the tooltip. This is significantly higher AP scaling than most of our combo point generators - Mutilate, for instance, is about half that despite costing half again as much energy - but I suspect that's intentional because it doesn't scale with weapon damage.
2) And that's significant, because weapon damage appears to be way higher in beta than on live. The legendaries tooltip is 1572 DPS on beta vs 786 on live - almost exactly double. And its not just that the DPS calculation is being done wrong; the base damage of Golad increases from 990-1840 to 1981-3680. Again, doubling.
Also note that this is not unique to the legendaries - all the weapons I've seen do twice as much damage as they do on live. I suspect they've decided they want weapon DPS to be a larger contributor to our damage, so went through and doubled the damage of all weapons, and will rebalance our DPS accordingly.
3) That said, nothing that's happening with Crimson Tempest makes any sense whatsoever. Consider, for instance, the tooltip damage with 12828 AP:
| CP | Damage | Increase |
| 1 | 2212 | |
| 2 | 4043 | 1831 |
| 3 | 7391 | 3348 |
| 4 | 12013 | 4622 |
| 5 | 14855 | 2842 |
Not even the slightest shred of a pattern; compared to, say, Envenom:
| CP | Damage | Increase |
| 1 | 1449 | |
| 2 | 2899 | 1450 |
| 3 | 4349 | 1450 |
| 4 | 5799 | 1450 |
| 5 | 7249 | 1450 |
The fact that CT also does more damage than Envenom might be a concern - as that would imply it might well be worth mixing into our single-target rotation. Fortunately (?) when you actually use CT, it doesn't anywhere close to that - a hit on an unarmored critter was doing between 5742 and 6198 damage in my limited testing.
Also interesting is that the bleed doesn't do 30% of the damage of the initial hit. It seems to be closer to 25.9% - that is, each tick is doing damage as though it were doing 1/7 of 30% of base damage... but there are only 6 ticks. It might also be noted that despite hits on the target dummy spanning over 100 damage (3122 to 3241) the ticks all did 139 damage, which additionally implies that its not doing 30% of *actual* damage, done, its doing 30% of some theoretical *base* damage. But it's still mitigated by armor for some reason.
In short: CT is buggy as heck right now. The tooltip doesn't make any sense and has almost no relation to the actual damage done. I suppose this isn't too surprising as they've just added it to the game - clearly there will be a numbers pass sometime before launch - but it is still striking just how little sense it makes.