I think I preferred ARAM without Warmog's
I would like to preface this by saying that I fully understand the issue with the strength of poke comps in ARAM. I understand that sustain is required to help counter the poke, but I feel that Warmog's is not the way to go about it. I remember a few people on the boards lamenting over how Warmog's is essential to ARAM during the Butcher's Bridge event. I agree that poke is extremely powerful in ARAM, but Warmog's is in my opinion not a healthy solution to the issue of poke.
Warmog's rather feels like the reason why Riot nerfed Fleet Footwork, because damage doesn't stick to the champions that use this item and build enough health to activate it. It feel more like a punishment for catching out a bruiser or tank but not having a long enough cc chain or enough damage to kill them before they can get away. The item creates a two scenario system that feel outright dissatisfying to play against, in which you either catch them out have enough damage to kill them or you have to let them go and they comeback ten seconds later with you having effectively done nothing but waste mana and resources.
Understand I have no issue with sustain in general, but I do feel that warmog's is a special case, because the item itself does not have an issue when examined in a vacuum. It's the item that gives tanks sustain and that is it's purpose and there is nothing inherently wrong with tanks having sustain, the issue arises when you place such an item in a place with such limited sustain. ARAM is defined by the inability to go back to base and heal up before the next fight. It's a game mode in which mistakes hold a lot of weight and healing is something that is to be fought over in the form of the health relics. It enforces a style of play that asserts that healing will cost something or force you to put yourself out there. By fully circumventing this style of play, Warmog's makes one champion's mistakes at best into nothing and at worst into a punishment for the opposing team. It fully negates the purpose of the no backing rule and severely outclasses other forms of sustain.
All in all I do not believe that tanks don't deserve a form of sustain, but I do feel that the form of sustain they get should be moderate and not just erase their mistakes outright like Warmog's. I feel the item needs to be replaced because it is seems fairly unhealthy, but tanks deserve some sort of sustain. At the end of the day, this is my opinion, feel free to comment as you wish about your thoughts on Warmog's.