WAR is certainly receiving a buff. Fell Cleave hasn't been nerfed yet to our knowledge, and Upheaval is pretty much another 300 potency ability, along with the fact that Infuriate's recast is shortened by using Fell Cleave, so up to about 30s taken off the 60s recast. Berserk is receiving a tiny nerf by changing from +50% every 90s to +30% every 60s, but with everything else in place, WAR is coming out far ahead of what it used to. My guess is it will be doing comparable, if not more damage in proportion to what it does now, even after the tank nerf.

For PLD, it really needed those new abilities to keep up, and what we've seen now is not enough to make it on par with WAR. I think the difference though between PLD and WAR will remain the same as MTs, but they'll be closer when PLD is OT.

As for DRK, we do know we're receiving more offensive ability, but we simply don't know enough yet. Will SE decide that DRK should be the heavy hitter, or will it remain an "in-between" tank with a slightly more advanced play-style approach? My guess would be the latter, and if I were to wager, I'd say the hierarchy of the tanks' DPS will stay the same, with the big difference being that the gap is smaller in OT positions.

Something people forget is that PLD had more people playing it than DRK for raid in 3.x because its mitigation, image, and ease of play appeals to a wider crowd, so I think they're helping out this crowd with some extra tools while still giving the rest of us what we want as well.