As an ex-Tyranid player, I can attest that revision is absolutely preferable to a rework. There is nothing more discouraging than getting a shiny new codex only to find that half the army you invested so much time and money on is now almost useless. Reworked codices seem to be plagued with nerfs whose sole purpose is to push new models.
With that being said, there is a fine line to walk between ‘revision’ and ‘FAQ cash grab’ (*cough* 7th edition). Having too few changes can also leave the player feeling cheated. The Eldar codex seems to have struck a pretty good balance between the two (possibly because there aren’t any new kits?). Only time will tell if the new Eldar codex is a fluke or not.
Jaded Gamercast 
As an ex-Tyranid player, I can attest that revision is absolutely preferable to a rework. There is nothing more discouraging than getting a shiny new codex only to find that half the army you invested so much time and money on is now almost useless. Reworked codices seem to be plagued with nerfs whose sole purpose is to push new models.
With that being said, there is a fine line to walk between ‘revision’ and ‘FAQ cash grab’ (*cough* 7th edition). Having too few changes can also leave the player feeling cheated. The Eldar codex seems to have struck a pretty good balance between the two (possibly because there aren’t any new kits?). Only time will tell if the new Eldar codex is a fluke or not.
Sometimes I pull out my 4th Edition Tyranid Codex and just sob quietly until the sweet embrace of booze-fueled sleep takes me.