Blindsight

[Ridley's Cohort]

I think the blindsight spell ended up at 2nd level because of comparison to invisibility purge. IP is 3rd level and reveals nearby invisible creatures to everyone. A designer probably reasoned that, since blindsight only reveals invisible creatures to the spell subject himself, it must be a less powerful spell. He forgot that it has the side effects of granting darkvision plus infinite ranks in Spot.

If it is true that a designer reasoned that way, the designer in question should learn the rules and spend some time around the game table before picking up his pencil again IMNSHO. The proper spell to compare with is not Invisibility Purge -- it is True Seeing. If it were just a matter of perceiving magically Invisible creatures, it really would not be a big deal. But Blindsight is so perfectly efficient against concealed or hidden creatures that it ruins one aspect of the tactical game.

My preference was to give most 3.0 creatures with Blindsight an ability more in line with Scent. Blindsense seems like a reasonable compromise.