In Wild with additional Kazakus (Mage, Priest and Warlock) it’s better, but they have some other minions:
Inkmaster Solia for Mage: just worse Kalecgos or Dragoncaster with no-dup requirements which is very weak so most of highlander Mages does not play her
Kruul the Unshackled for Warlock: is very powerful in theory, the fact is most Renolocks never use it as you rarely have enough demons and him in hand, usually you don’t or you already cheated them with Voidcaller and legendary weapon
Raza the Chained: after un-nerfing is being played again, but it’s not super uber strong card
Anyway it’s Renolock and its different versions (Mecha’Thun, N’Zoth, Gul’Dan, aggro/deathrattle and more) that lives on and on through all expansions, always Tier 1-2. Reno Mage is old archetype but it took so long before viable T1 (OTK giants) archetype was born. Priest has Razakus machine gun which was dead and now is back.
Kazakus is e.g. very good for control warlocks (polymorphing which they haven’t) or Mages for damage, it’s very suitable and next to Zephrys and Reno TOP3 highlander card
Edit: I do not agree with guys above: I kill people with Reno Mecha’Thun Warlock faster than with OTW Giants Mage, also winratio is higher. Just don’t netdeck and think, most people who say that Highlander Mage has better OTK didn’t try other options at all.