I must disagree. Mainly because Terra is only 4 E. and he is quite generous with the stuff. You could always farm him in normal with your 61s.
If they were to implement something like that I would suggest you only get eridium from some kind of machine that gives you only 2 per etech weapon. I'd go with that for Torgue Tokens with purple or orange Torgue Gear. Maybe Seraphs could give 5 crystals.
The major problem would be then people duping stuff to get to currency they need. Well I guess duping has always been the problem. Wouldn't change anything actually.