There are way too many good $4s that would be just outrageous if you could play them 3 times on your third turn. KC + Cutpurse, KC + Sea Hag, KC + Marauder, KC + Young Witch would all be pretty devastating if you could connect them on your first shuffle. I wonder if the power of these combos would outweigh the unlikeliness of connecting the KC and the terminal - it's rare that Throne Room/X is the correct open, but would an extra play of the terminal change that, so that that KC/X is the correct play?
With KC at $3, you probably ought to shoot to pick up multiple on a single turn, in almost any kingdom with any kind of +buy, virtual or actual. Trying to drive the KC pile from the start doesn't help your deck at all, and is probably slower than using the KCs to your advantage in most cases.