I don’t tend to use potion throwing except in extremis, because I object to using such a dubious mechanic, but even without it I’ve found the game is possible without a cleric. Particularly if you have another class that can heal other party members in an emergency like druid, bard, ranger and now paladin.
But while I agree you don’t need a traditional heal and buff cleric, I still found the game satisfying, interesting and different to play with a Life cleric fulfilling that role, especially as I tend to use Shadowheart as more of a magic damage dealer and rogue substitute, and because there are a few items scattered around that apply extra effects on healing others, such as giving a blade ward or allowing the healed companion to disengage without using an action. Okay, he didn’t deal as much damage himself as a Light cleric would, but the extra damage he helped the party do by keeping them on their feet and able to use their own actions and bonus actions to fulfil their own roles rather than use or throw potions could well have made up for it. I’m sure a Light cleric would be able to heal and buff well, too, but I enjoy making playstyle and spell choices for roleplay reasons, so it felt right to go all in on the traditional healer approach with a Life cleric.
I think all the cleric variants in the game have a playstyle that suits them, and I’m intending to try all of them. I’ve only done Shadowheart as a Trickery cleric yet (though I have a custom one in mind) and my Selunite Life Cleric so far. I am looking forward to my dwarven Light cleric run at some point too.