however Blizzard must have done something whit the dropprate of Plan's.
think i have found about 16 or so after 17 hours of play.
(and thats not only the new ones.)
From the patch notes:
The drop rate for Blacksmithing Plans and Jeweler Designs has been increased by 400%
On your other issue, if you aren't seen particle effects at all you might have a video card/driver issue. It could potentially also make you not see the beam of light when a legendary drops. You should investigate that and to be sure - create a topic on Battle.net explaining your issues in more detail.