+32 power, to me, is not that big of a difference when you are talking healing. +32 Alacrity was more of an important factor pre 1.2, but now, Sages just don't have to worry about stacking as much of these stats. If you are lacking in the power/alacrity department, then maybe it would be a good idea to have some extra stats put into this area. I would not sacrifice the 2 or 4 set bonus at this point in time to get a little extra power/alacrity though. +50 to force is an additional 2 to 3 heals and the cd reduction of HT from the 2 piece bonus means you will be able to use it more often. I believe the diminishing returns on crit is capped at 40% and surge at 60% so if you are over the DR cap on crit/surge you might want to reduce those a little and toss the extra into power/alacrity.
Basically, what you want to try to do, be it pvp or pve, is balance out your stats and get them as close to the DR cap as possible. You were right to stack crit/surge first, but now it is time to try and get some balance with the other stats. I would say if you have to choose, take alacrity over power as alacrity not only speeds up your casted heals but also makes your HT tick faster, acting almost as a single heal with the added benefit of crit chances on each tick.
Good Luck