Honestly, I remember playing Civ2 with its graphics and those being some of the best gameing sessions I ever had. Graphics only mean as much as people let them.
The other day, after hearing about MoM for the first time, I Dl'd it (its freeware now) and had a great time. I stopped playing only because the game suffers from late game "janitor" syndrome (ie you won, but you have to find EVERYTHING and kill it to be acknowledged). But the graphics didn't mean anything to me. The game was fun, the hell with all else.
Now, recognize that I still love great graphics, but if eye candy is all a strat game has going for it then you will quickly lose interest. If these somewhat styled graphics allow me to have thousands of units on screen for a battle, then the hell with 3d crap. Also, the more involved your graphics become the harder it becomes to mod. Most half life mods die not because of a lack of coding, but because the modeling and texturing is both hard and unrewarding. Most people bash modders for simplistic graphics, despite the effort that goes into them and the quality of the gameplay.
Oh, and BTW I like the grphx as they are (assuming shadows give em some depth)