I can say so far that I am satisfied with the skill tree changes. All in all it seems that what they have done was not at the detriment of the way the classes play, which makes me happy. What I mean by this is that they made little tweaks, but they are mostly in the skill result such as proc effects. I can't say this is the case on every change, but it is what I have noticed for myself.
Shattner: feels a little more durable, but since all we have run thus far is HM FP's and I'm used to seeing raid damage, that may just be a misconception. However, I have not had to change my skill rotations from the tanking point of view unless I need certain procs at certain times. Energy Blast seems to be up frequently enough that I don't believe there will much of a need to "balance" the use of that vs. just letting Power Screen stack. I am looking forward to the Shoulder Cannon and seeing how that works. Energy managment seems about the same if not a bit better with the 100pt change. Also interesting is they granted us a new Aggro dump.
Simmet: Talks like a Sentinel, Leaps like a Sentinel... must be a Sentinel. All in all, not many changes here just yet. I actually see the majority of improvement coming post-51. If I had to choose anything, they REALLY focused on Watchmen's DOT damage and application with the skill tree changes. Managing my focus pool seems about the same.
Marrkin: Big improvement on Healing trance from what I can tell. Before I would crit around 1100-1200 and then it would drop to 700-900 per tick. Last night it was doin Crits over 1600 and the ticks were frequently popping over 1100 (non-crit). Otherwise not alot of change to the gameplay except the changes to Resplendence. Now it is a choice between Noble Sacrifice without a Force cost, or Salvation with a 33% increased activation. Interestingly Resplendence is stackable, so multiple NS uses are possible without force cost. Salvation wipes all stacks.
Managing my force Pool seems about the same.
Also, no CD on Force Armor was great

Also: It was friggin awesome running stuff with guildies again. No pressure, no BS, We had fun and even picked up a number of BH pieces lol. (Boo to the double Esseles!)