All classes are viable, all class setups are not though. If you wanted 2 pure melee you'd have to understand it would be hell and relying on scrolls early on. Then you'd coast into easy mode once both know flurry and whirlwind.
What you have going right now is perfectly fine and many people are doing it, like many many people are doing mage + sword n board warrior with the mage buffing and both lone wolf and they are doing just fine. You just need to get in a better habit of controlling the battlefield. Go get some money and learn lightning bolt or get some scrolls of it for your mage. Make it rain before the battle begins, cast lightning bolt at whatever puddle has the most enemies in it to stun them right off and start the battle with that instead of just walking into it. Start using chilling cold to take others out by freezing them and ice lance as well since while the rain is up its super easy to freeze and remove them from battle for a few turns.
Just as you were complaining about getting knocked down too much and not doing anything, you can and need to be doing the same stuff to the enemies. You're also comparing your warrior's melee attack to a fireball spell from a mage in your last post, compare the fireball to dust devil or whirlwind and suddenly the warrior is doing a hell of a lot more. My mage with like 18 in can fireball for 150ish + 70ish burning per target. So 220x6 if 6 targets like you said. Meanwhile madora can walk in there and use dust devil for 300 per target, or whirlwind for 400 per target. or both back to back. Oh look who did more damage?
Don't complain that your low level and underskilled warrior isn't as good as a mage when you don't even have power stance on him and you aren't playing to his strengths.
