I have five toons in my legacy so far. To this point, the Cybertech crafting skill seems to be the most useful as all character types need the armoring pieces. For this reason, two of my five toons are Cybertechs. HAving said that, the most frustrating crafting skill so far has been the Artifice skill. For some reason, maybe just random, dumb luck, it often takes dozens of greens reengineered to learn the blue schematics. Purples have come a little easier than blues, but my observation is purely anecdotal as I don't have the actual numbers.
I have also noticed that it seems to be more profitable just selling the materials. In the case of puple hilts, I often have trouble just breaking even as far as value of materials VS the selling price of a purple hilt. This says nothing of the cost or time I incurred to learn the schematics. On the other hand, purple hilts are not available much of the time on GTN. Probably because it's not worth it to the crafter to craft and sell them. It's a catch 22 in a way if you want the purple hilts. Please note: I am speaking of hilts< lvl 50. I have no experience yet with lvl 50 hilts.
One last frustration: has anyone else noticed that the alleged high crit level of certain team members don't seem to produce any more crit than a non-crit crew member? I have.
RNG is a *****
. You may be having trouble with RE and crit crafting but someone else is getting VERY lucky. Over the long haul and over all the crafters in the game the numbers balance out.