Damn, this sounds like my kind of game! I hate games that require micro because I always end up getting my ass kicked.
My usual strategy consists of: create a mass of units, preferably a single jack-of-all-trades unit, mass-select them and click inside the enemy's base. And forget all this "rock-paper-scissor" stuff. Juggling anything more than two or three kinds of units is more than I care to handle.
You're not going to like SC then. Just because there's less micro tactics, doesn't mean there's no strategy. If you just build units and hurl them it'll be very easy to repel them.
For example, I was playing the skirmish map in the demo. The two land choke points were obvious so I built three laser towers and a concrete wall in front of those. Concrete walls are extremely tough against direct fire but go down under explosives fairly well. A few minutes after completion, the AI sent a column of ground units, mostly direct fire and AA. Three laser towers slaughtered the entire mass because they had to thin out through the choke point and slowed against the concrete wall which also blocked their direct fire. The laser
towers could shoot over the walls >:-). The little damage the walls took were quickly repaired by the Engineer I set patrolling the fort.
Later on, the AI built some missile units and utterly annihilated the little fort without taking any damage =/.
Incidentally, the AI gets to have these kind of setups premade in the campaign missions. I generally have to rely on artillery to lob shots over the wall (there tends to be a cluster of Point Defense and Anti-Air Towers behind the walls so direct fire and bombers get slaughtered).