I'm glad it's being removed - it should be removed from the game entirely.
I agree with you that Grievous Wounds is a powerful effect, but it's one that's not very fun for the person using it or the person being hit with it. The fun to power ratio is just too low, and I think riot can come up with better ways to deal with heavy sustain that are more interesting for both sides.
I can understand the desire to remove Grievous Wounds but it's not because it's lacking in the fun department. "It's not appropriately fun for how powerful it is" is very Riotspeak. Large amounts of lifesteal is very powerful too, but I could very easily argue that that's a pretty boring mechanic as well. Removing a mechanic from the game really needs strong reasoning and that reasoning exists for GW, but I'll get to that later.
I mean, personally I find GW fun. One of the few things that made Miss Fortune interesting before was that she was one of very few champions that could apply Grievous Wounds, when needed. It was an interesting tool in her kit that allowed her to win trades (particularly post-Vamp Scepter) in a much more unique way than just a steroid that outright allowed her to outdamage the enemy ADC. Having a mechanic in your kit that can be incredibly potent in a few situations, but only in those very niche situations presents interesting questions about when to apply it and who to apply it to. Grievous Wounds can even be quite thematic, it makes perfect sense on Death Lotus for example. You're throwing up to 10 daggers into someone, it's gonna be pretty hard to patch up those wounds. On the opposite side of the fence, Soraka's ultimate removing Grievous Wounds is hugely thematic considering it's Soraka's desperate plea for life to prevail.
The actual problem with GW and the reason Riot have been slowly removing it from the game is how binary it makes sustain in the game. Heavy sustain champions can be complete raid bosses if left alone but with Grievous Wounds on them, their strength has been completely nullified. An ignited Mundo, for example, is essentially 50% effective. Riot has an immensely tough time balancing sustain so that it's viable in a world where GW is common (how does Mundo function against a team with current Miss Fortune, a Morellonomicon mid laner and at least one enemy champ with Ignite off cooldown?) without being out of control if Grievous Wounds can't be applied to them.
tl;dr Grievous Wounds isn't getting removed because "it's not fun", it's getting removed because it's too hard a counter to sustain to be an easily balanced mechanic. What they hope to replace it with I don't know, but they have commented on it being uncomfortable for them to have it be prevalent in the meta recently - most notably when they buffed Athene's Unholy Grail in an attempt to make Morellonomicon less dominant as the premiere mana regeneration item.
What I find hypocritical is that they didn't remove GW from Morellonomicon, while the stats in themselves are so good that the item isn't even built for its passive, and would still be core on a lot of mids without it.
Meanwhile, GW was one of the only reasons to pick MF over almost any other ADC.
say's, "I'm still cool though, right?"
replies, "#&%$ that guy."
Yes, it's so good that Miss Fortune no longer had grievous wounds. I agree, it should be removed from the game.
All hail our new overlords, 
Down with counter play and balance! Begone with ye!
I agree.
Yay healers :D 
I'm glad it's being removed - it should be removed from the game entirely.
I agree with you that Grievous Wounds is a powerful effect, but it's one that's not very fun for the person using it or the person being hit with it. The fun to power ratio is just too low, and I think riot can come up with better ways to deal with heavy sustain that are more interesting for both sides.
Then remove Grievous Wounds abilities and add an AD item like Executioner's Calling.
Because why would mage the only who can deal with sustained champions (ignite excluded) ?
As much as I agree with hating grievous wounds, I'm fine with having it on Morellnomicon. One item that only mages and assassins can use to help kill tanks like Mundo is good for the game, but the BS stuff like old Fizz W and Kat Ult doesn't really make sense nor is it fair. Most champions need to pay 2300 gold just to get grievous wounds while others had them off a single ability. It just doesn't make sense.
Okay, it should be okay for them to remove literally every way for an AD champ to apply grievous wounds and not leave in one ad carry pick to deal with it if they've got a super sustain team? IE< a swain.
