No it is not. As ematanis said, lvl 61+ gear requires different mats, so DEs won't work for Expansion-level gear, and Tomes of Secrets have been converted into DEs, so if you have a lot of Tomes then they'll all turn into DEs. Basically, if you plan to buy RoS, then there's no point in getting a lot of DEs, and if you don't plan on getting RoS, then it would be more effective to buy a lot of Tomes of Secrets so that they can be converted into DEs.
Also, for gems, if you don't plan on buying RoS, you should buy up a lot of gems. The new PTR/RoS beta patch made Torment difficulty available at lvl 60, instead of lvl 70, but as far as I have found, at lvl 60 the highest gems that drop are Flawless Squares. Some people on the PTR said they've found Marquises at lvl 60 on Torment, but I've played Torment for about 6 hours and only found Flawless Squares. The overall cost for making Marquise gems has been dropped to a few million gold per Marquise, but they take a lot of Flawless Squares to make. If you don't plan on buying RoS, then it's probably in your best interest to buy whatever gems you can get the most of for the cheapest cost; I haven't checked live in a while, but last I checked, each Radiant Star cost about 20 million gold, and on PTR the cost of making a Marquise gem can't be more than 4 or 5 million. Thus, if you're not buying RoS, buy up as many gems as you can so that you can fill all your gear with Marquise gems.
