I find the "get corroded" and "get weakened" advisor tasks to be a bit over the top. These tasks require you to incur an onerous number of stack, and most dungeons don't have any source of weakening or corrosion. Combined with the fact that you will usually avoid weakening and corrosion, this makes them nearly impossible to fulfill in a reasonable amount of time with natural play. I've currently got an advisor task for 106 stacks of corrosion, that's just too much!
However, both of these debuff tasks are exceedingly easy to clear if you're underhanded about it. Prep Earthmother on Ick Swamp and start clear-cutting and you'll rack up hundreds of points of corrosion in under a minute. For weakening, take a dwarf monk into Den of Danger with a Tikki Tooki prep. Find a level 1 meatman and wrestle with him until Tikki has sufficiently weakened you to clear the task.
I don't think corrosion and weakening are working out well for advisor tasks, and I think you should remove them from the rotation.