I think a big part of the problem is that legendaries are like other highly unique items - they are simply fun to use with no alternative. When a boring stat stick is BIS, the players who most enjoy getting a big number in details at the end will be excited to get it, but I suspect most players who value how their character feels won’t really feel the same excitement even if they use it because they want to perform well amongst their peers. Whereas most of these unique on-use or proc items are simply satisfying when they go off, and even if they were tuned to be in line or even worse than the boring stat stick alternative the latter group would still chase it. Having the super unique, fun item also being the super BIS performance item means both groups will chase it and any alternative will make both camps feel dissatisfied with not having the shiny toy.
I get the frustration over the axe, but has there been any proof that warriors (and paladins and DK for that matter) are tuned around the axe? There are specs above and below the specs that can use the axe on the meters, and if the axe-wielding specs truly were tuned around having the legendary then shouldn’t the average performance across the entire player base put all those specs at the bottom? I mean across all mythic groups for the last day (to account for the buffs that went out this reset), both fury warrior and ret paladin are in the top 10, and unholy DK is in the top half as well; go to heroic to find ret paladin is top 3, and arms warrior joins fury and unholy DK in the top 10.
Unless Blizzard has confirmed the specs are tuned around the axe, the data just simply does not seem to bear that out in any way.