I played most of VE 1 and what I liked most about it was not the custom units - quite frankly, it would not have made much difference if the immortals had been dragoons instead. What made it really awesome was the clever use of sounds (especially in the intro cinematic), superb voice acting and what would be termed "professionalism" per the rules, ie. making sure everything is timed right, no silly bugs, text properly aligned, etc.
Modding is great and it will be even better with SC2, but you should be careful that it doesn't go completel overboard ("modding for the sake of modding"). But then again, I'm a story-freak - an intriguing story with some interesting mini-games (instead of survival, base building and similar) and I'm hoked
