With the prevalence of stacking spell vamp/lifesteal, and with how many champs self heal through abilities, grievous wounds seems to be the best counter to keeping them dead. Tryn, ADC's, Mundo, Vlad, Yorick, Xin, etc all base their existence on how much they live just on regen/sucking health from others. All that being said...our options to STOP that insane regen from happening are extremely limited, and come out of odd builds. Avarice Blade, while good for gold generation, has no other decent stats, and what it builds into, Executioners Calling, is weak 100% outside of inflicting grievous wounds. Morellonomicon is a great all purpose AP item, but it's under utilized from I've seen, mostly because outside of support not many worry about getting Kage's (side note, I don't ever when I'm mid because I get more gold generation killing creeps with other items, i.d. needlessly large rod, Chalice, etc). I know of 2 champs who have abilities that inflict grievous wounds, Tristana's E and MF's W.
So, maybe griveous wounds is just op, but with the rash of people who can regen, and do it insanely well, it seems like maybe we could get some more item choices to apply them? Just a though.
All hail Zultan.