Being a one lane map doesn't excuse poor dodging abilities. I'm not saying everyone needs to be perfect at dodging but if the argument to keep it is because a player can't avoid poke, then Warmog's being a necessity is not an issue, it's the player's issue.
Aside from Warmog's there's plenty of ways to build sustain without it. You can still build plenty of base regen through other items which already made to counteract poke such as
and
. Additionally taking the Second Wind rune also helps return some of the hp lost in a trade. Assuming this is all from a melee/tank perspective.
Fighters and marksmen still have access to the lifesteal stat so Warmog's removal isn't really an issue for them.
Many of the long ranged AP champs already have enough range to keep them away from taking unnecessary damage and can already go on legendary killing sprees without and complications. Their only limit is that eventually they'll plateau in damage and will need to spend their gold to bring their back up.
The biggest abuse case that really comes to mind is Veigar building it, since his damage really comes from just stacking his passive on a small map riddled with champs to stack on. Vladmir is a strong case too but even with a proper build he'll be self healing like a maniac without the need to build Warmogs.
Annie is another case too in the scenario where really she just needs to apply her massive to stun to contribute and gain gold. The HP helps her make sure she gets in with the stun and unload her kit without having to worry about trading her life.
But considering the usage of Warmog's as a means to prolong the game until your can get items to feel effective. Then surely it means that you're likely to play a long, drawn out ARAM match, with a champ you don't think makes for a good candidate for the map, against a team that looks poised to win from champ select. Then you're already having a bad time. Just let it end and find a new match. Your friends are probably all waiting for you to get out of your supposed quick 18ish minute match. But noooo, players had to go and build Warmog's so they wouldn't lose. Matches slowly become 20 to 25 to 30 minutes commitments. So much for a quick game of ARAM.