I actually bought Masters of Magic when it came out, before I even owned a PC. I saw it and thought 'Omg, they made the game I dreamed of!' Yeah yeah, I know.
I thought the system of 'swords' and 'shields' with a 'chance to hit' while basic, worked extremely well.
I knew each shield on my unit or heroes had a base 30% chance to block a point of damage. I knew each sword represented a 30% chance to do 1 point of damage.
I also knew, better units (IE, heroes, more advanced units, seasoned troops) would gain bonuses to hit. Thus making each 'sword' have a better chance to overcome the defending units defenses and doing its point of damage.
Good heroes (through equipment, spell buffs, levels gained from experience, traits, etc) might only have 10 shields, but could have 70-80% chance for 'each' shield to block a point of damage, whereas a low level right out the starting gate hero would not have such bonuses.
What it meant in the long run is, I could tailor my heroes into tank types if i wanted, high attack/hits so as to be lethal in combat, huge resistances to make them almost immune to spell damages/debuffs. That is the element that really put the whole RPG stats/improve a hero into the game imo.
Even those big creatures could still be scary. A dragon might have 30 attacks, with a 15 strength breath attack on top of that. His breath might be 'armor piercing', which halved the defense of the defending unit. He also might have the first strike ability, allowing his 'attacks' to hit units first on attack AND counterattack, unless such units had the same ability to negate his advantage. He also would have a massive hitpoint pool, to soak up damage before he died.
People, myself included, expect end game monsters and heroes to be these tough, hardy units.
When I played mom, how did I tackle such units? I didn't always uber enchant/gear heroes and get tons of levels and then go steamroll these things. Often I would use the best trainable troops I could make, like Dwarven Hammerhands, built in a city next to resources that improved my units attack/defense. I would then 'enchant' the snot out of my hammerhands, and maybe bring a hero along into battle with the stack of hammerhands to provide spell support (buffs, heals, debuffs) and let my hammerhands 'work' on killing those dragons or other nasty things. Sometimes all my units would die, and I would have to retreat with my hero, and bring back a 2nd army to finish off the tough nut to crack monsters/monster lairs (who, btw, kept the damage you did to them from any previous battles) It cost me a lot of gold to throw armies at these tough monsters, but it was a strategy to whittle them down to claim those nice rewards for killing the lair! If I overextended myself trying to crack these lairs, enemy wizards would come in with big armies and make me pay for mobilizing my best units and taking them away from my cities!
Criticize it if you want, but I found the system to work out really well. It made my heroes feel like heroes. I think with enough care and time, heroes should approach amazing power. It should be slow, expensive, but achievable. Just about any game like this with 'hero/champion' units follows the path that these units are a more valuable resource than a common garden variety unit. Age of Wonders, Heroes series, Mom, even MOO with 'heroes' attached to ships for bonuses was a great idea!