So, to sum it up.
Hunters and Rangers are waste.
Veterans are backbone of the army, it's good to build them in a city with free perks. The best could be upgraded to Blademasters and/or Paladins.
Rogues are cannon fodder. The surviving ones could be upgraded to Assassins if Lunord temple is available. Upgrade to Cutthroats without Lunord temple is mostly waste of money.
Mages are for special tasks like eliminating Greater Fire Elementals, plus for some ranged support.
And the ultimate goal is to survive before you could start building temples.
For a different experience, I basically only build Hunters, Mages, and Settlers. Rogues remain fodder and are rarely built. In my current (90ish turn Impossible XL Island) game, I have yet to build any warriors or Veterans. Found or rewarded melee units are adequate until a Temple is built. I do choose a melee temple unit for Portal World/Capital/Avatar slaying. A single Hunter in each city on sentry makes for a great reaction force, and if needed can be upgraded to a Ranger if a dangerous threat appears (Like a "Kill the Heretics!" mission).
Resource perks are key to this being viable, I've found. Without the Silver Armory and Enchanted Weapons, Hunter/Rangers don't cut it for my playstyle.