10% extra Critical strike damage will only net you 2.5% extra DPS. Simply put, it's not worth the 30 points or so to get there unless you're overflowing with extra CP's. (Also, this is before critical mitigation, if referring to PvP, see Nirnhoned and RESISTANT in the Warrior.)

This assumes you're at 50% critical chance, as it is. If you're below that, the DPS increase will be even less.

Here's why:

Critical damage is +50% of your base damage. If you have a 50% crit chance, this is happening 50% of the time, meaning you're getting a continued increase average of +25% of your base damage.

When you add points into Precise Strikes (melee) or Elfborn (Spell), you get an increased percentage of the Critical damage, not the overall damage.

So, with that first "1%," your +50% increase goes to 50% * +1% or .50% * 1.01 for an actual increase of .5%.

Your crit damage now goes from 50% to 50.5% of your base damage.

However, that only happens when you crit, so at 50% crit chance, that works out to be 25.25% overall DPS increase.

And that's the biggest increase with your very first CP in the passive.

So, you can sink 30 points in to get 2.5% DPS increase...or you can get the Shadow Mundus and do the same for 0 CP's.

You'll get more bang for your buck increasing your base damage stats (elemental exprert/mighty) as those will increase your overall DPS 100% of the time, and increase your Critical damage automatically due to how Crits are calculated.