I think perhaps part of the issue is that up to MoP you could get Normal equivalent gear but there was no Mythic. You were just one tier below max. WoD kept casuals at a much lower level AND gave them very little content. Legion did not really give certain access to that ilvl but there was always TF. BfA gave full heroic if you bothered with WM (easy conquest cap) and also had Visions (I won't count HC Warfronts because that was still something you had to PuG, even if vastly easier than anything else giving comparable gear).
Meanwhile SL required an extensive grind to get you to that ilvl with Korthia relics and a much easier grind with Cyphers (but no full gear).
Ultimately it's about the ilvl. And the argument ofc is that you don't really need that ilvl for that kind of content which is very much valid; you don't need it at all. But it definitely was a motivation to do content. I guess it's a psychological thing; people will not mind grinding for months if it gets them at just a bit below the best. They will not feel the same for something that's much further below.
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I think it can be done, you just need to work on the SFX more; use a cooler, more saturated flame color and make it swirl and envelop targets instead. I mean the phoenix is a beloved fantasy staple and they heal with fire.