For me MOM was not about Nostalgia (as I STILL play it to this day via dosbox, I own the original on floppy)
There's just something about the diversity and customization that gives personality to the game.
Sure the races are unbalanced, but the way the races are unbalanced leads to some interesting and diverse play styles.
Take for instance - the lizardmen/klackons/gnolls, they don't have a lot of buildings, therefore they don't provide as much bonuses as some other races . Some players may view this as a weakness (indeed the lizardmen barely have any production bonus buildings at all!), but personally for me - less buildings simply mean that I can quickly get to the race's end tier unit.
Dragon turtles, Stag beetles and wolf riders are overwhelmingly strong on the early game, as they can easily be cranked out in a few turns, while races like high men who starts slowly would still be stuck with their puny swordmen .
What I like about MOM is that I am not stuck with a particular "faction" or "race", I get a starting race and from that starting race I can conquer and assimilate races into my empire to aid in further conquests. So if I use the lizardmen, I will have a strong early game and if I conquer other races capable of producing strong end game units and bonuses, I will have offset the weakness of the lizardmen that I started with at the beginning.
Balance tends to be "relative", as some races fare much better on certain landmass size settings.
Ex: Swimming Lizardmen, Flying Draconians fare much better indeed add to their advantages when the world landmass is set to small. Other races would have to tech up to build ships to expand to other places.
One player's perspective of weakness is another's perspective of strenght is my 2cents.