I didn't even know people thought that 2H melee was the strongest until I read this post, but I guess it makes sense that it's top tier. I always thought top tier was was Ranger or Rogue, and Summoner, with mage close in tier 2. That said, I breezed through the game with two elemental mages(one slightly more focused on buffing support, and my main hitter with glass cannon), with Ifan as Ranger with Glass cannon and execute, and Sebille as rogue. Great comp, and mage hits just as hard as others.

My Geo/Pyro mage(and later added heavy hitting Air spells like chain lightning against earth or fire immune), blew almost every enemy up on the first turn starting from high ground(and this was before I got crits on spells). Rarely did I find enemies that could take both Earth and Fire until later, and by then I had air as well.

My first turn went like this, Mage always going first: Explosive mine+impalement or fireball, or for fire immune: impalement+ fossil. And other combos, depending on the situation. I pretty much always ended my first round with 2 or more enemies dead, or close to dead. The rest was Sebille and Ifan cleaning up the dudes with magic armor. Had some tougher fights endgame when their resistances and armor ramped up, but still got through it relatively easily.

Look up a guy on youtube doing an honor playthrough so far up past episode 70, he also has a similar setup to me, and he wrecks everything with two mages.