No
… that’s the argument
DKs, Monks, Demon Hunters - which one of these is a caster, not healer, but even so, why the hate towards healers and casters?
Evokers are battle mages, that’s their role, they aren’t full blown dragons, yes you can make an argument for it but at that point you are also arguing for mage tanks, warlock tanks, shaman tanks, priest tanks, and a whole lot of other tanks
It works for other games that are built with these systems from the ground up, but WoW isn’t - if you want Evokers to be tanks, you are asking for a different development mentality and philosophy in its entirety essentially
Which at that point, you’d be happier to find another game that does that, which allows all any and all, or no roles at all to be viable, for every class
Evokers not being tanks is good, and it provides better balance overall rather than having to figure out how to make a 25 range tank work - this is similar to how it is a good thing that Demon Hunters only have 2 specs, in that it makes it easier to balance things out as you don’t have a third spec be the “dead” one
Any argument as to why Evokers should be tanks is in short, a better argument to make mages and warlocks into tanks, and removing the group trifecta that exists in WoW that folks actually like
Or to summarize it as bluntly and quickly as possible … no, because the game doesn’t need more tanks, but it does need more casters and healers, which evokers are