Come now, you knew something had to give in some way when GWF could deal way more damage than Rogue and tank way better than GF.
Lets see class by class...
Wizard
Well, Singularity isn't quite as good now (one of the main perks was that Singularity affected a huge number of targets), Shard got nerfed hard (something tells me Shard was not benefitting from Armour Penetration before; it'll still probably deal crazy amounts of damage, just less crazy amounts), Steal Time is even more awesome than before and will deal crazy damage, Conduit of Ice is nerfed, Icy Terrain is better, RoE cooldown shenanigans are going to need re-evaluation again (RoE was actually worse with Mastery due to much higher cooldown), not sure if Chill Strike needed its little nerf, Magic Missile's position is shaken and feats will shake it further. Sudden Storm got nerfed, Eye of the Storm is dead in the water (90 second cooldown rofl), Fanning the Flames has a relatively minor nerf, Furious Immolation is buffed, Scorching Burst might actually have function for more than just Smoulder Refresh now.
The real hard nerf is for some of the feats, while other feats are going to become crazy good: Focused Wizardry is dead in the water and will be fully displaced by Learned Spellcaster, Arcane Enhancement and Wizard's Wrath are going hang around only by default.
Oppressor: Alacrity is crazy good now, Chilling Control is wtfpwn power boost to Sudden Storm, nobody still gives a shit about Glacial Movement because nobody still gives a shit about Ray of Frost, Twisting Immolation's daze effect seems to be actually worth a damn now, Shatter Strike HOOOOOOOLY SHIT does it seem crazy good next patch.
Thaumaturge: Assailing Force JEEEEEEEEEEEEEEESUS CHROIST it might be a boss-killer must have (twenty bucks says won't work on bosses and has ICD), Destructive Wizardry seems like a great deal (essentially permanent +5% damage), Malevolent Surge is not worthwhile anymore, Drifting Embers is still pretty meh, Elemental Empowerment got a big buff (some 700+ damage DoTs with a good weapon), Far Spell is a little better, Frozen Power Transfer is now roflmao megagood being +15% damage forever, other changes fairly minor nerfs overshadowed by the massive buffs elsewhere.
Renegade: Energy Recovery might turn Chilling Cloud into a legit tanking tool, Chaos Magic is less chaotic now and is completely overshadowed by the other two capstones (may be a great heal tho), Nightmare Wizardry will probably have better uptime due to increased duration, Phantasmal Destruction was nerfed in exchange, Chilling Advantage is more crit, Arcane Burst remains useless, Unrestrained Chaos remains meh, Masterful Arcane Theft is now the main reason to go Renegade.
Overall wizards are probably a little bit stronger afterwards but the orthodox build status quo has been severely shaken since you have to make up for nerfed base damage by stacking the new feats and many previous stand-out powers are nerfed. Yours truly is probably wise to use a potatospec to switch to Thaumaturge or Oppressor if they keep the changes like this. Chilling Cloud is a must-have now. Spellstorm Mage is shaken in a lot of ways (Storm Spell and Thaumaturge feated Storm Pillar are the reason to go Spellstorm now that Eye of the Storm is le dead) and Master of Flame comes out stronger in comparison.
Assuming these changes aren't rolled back or changed drastically.
Cleric
Has eluded the first batch of changes.
Great Weapon Fighter
GWF's exploitable powers (Roar, Takedown) got nerfed, the real change is that being a GWF is now a matter of choosing between Destroyer and Sentinel paragon paths (Sentinel has access to previous Unstoppable DR and then some). I'd say that's a good change.
Guardian Fighter
Block appears to be getting redesigned to work like Champions block (stamina gauge aside), assuming it no longer takes a Stamina/Guard hit from being hit. This would be a great change for GF and improve tanking greatly. GF will also have bucketloads of hp now due to Constitution granting twice the hp. Enforced Threat is super-mega-good with the new Mark changes and its buff (20 target max? r00fles!). Enhanced Mark is worthless, since Mark is now KILL ME I'M HERE KILL ME KILL ME NOW DO IT DO EET. With the new Armor of Bahamut, Protector might be close to indestructible.
Both fighters are affected by the PvP nerf of Frontline Surge and Threatening Rush.
Hunter Ranger
Aspect of the Serpent is easier to use and less confusing, some shit was changed for Constricting Arrow that I don't quite understand, and Grasping Roots was completely changed and there was much rejoicing among the PvP community. As for feats...
Archery: A lot seems to be completely changed. Keen Eye is new, Broadhead Arrows is moar crit, Unflinching Aim and Bottomless Quiver are crazy good, Rising Focus is insanely good, Stillness of the Forest makes you into a mega-sniper, Predator makes this even crazier.
Combat: Again, most feats seem to have been changed completely. Bloodletting is kinda meh, Serpent Weave seems really strong, Piercing Blade is potentially very powerful, Wild's Medicine might cause the Ranger to turn into Wolverine when combined with Battle-Crazed, Scything Blades seems to be the real thing you go Combat for, Battle-Crazed is like Bloodletting except might be actually good, Blade Hurricane HOOOLY SHIT if it's full damage instead of weapon damage.
Trapper: Even the name is changed. Ancient Roots seems really good for rooting, Deft Strikes is a reworking of Bloodthirsty from old Archery, Fleet Stance is eh, Readied Stance might be just for tier upping, Biting Snares seems really good, the Aspect of the Serpent class feature seems to be there to make this feat tree, encounter cooldown reduction feats are combined into one in this which might be a great pick, Thorned Roots might be good.
Ranger comes off much stronger in deeps if these changes stick.