Some numbers. With end-game gear and augments, we have roughly 800 points to spend on secondary stats, and the only secondary stats that matter for sages are surge and alacrity.

If you put all 800 points into alacrity, it will give you 18.8% base rating, and a 50% crit multiplier. Taking 200 of those points from alacrity and putting them into surge gives you 15.6% alacrity, and 71.2% surge. So for 3.2% slower casts, you get 21.2% bigger crits. Assuming a crit chance of 30%, that is 3.8% more damage on all attacks ( a bit more for Tk throw given its higher crit chance).

If you drop your alacrity to ~400, it is 11.6% activation time. The other 200 points can be put into main stat augments that both make you hit harder and add to crit chance.

For PvP, I would see it as debatable whether augments with endurance, power, or main stat are more beneficial overall. But I think putting more than 400 points into anything with severe DR (ie, crit, surge, alac) is just gimping yourself.