Reid's WCO is different than most WCOs (ala Bill Walsh, Childress, Shumur, etc) in that it primarily utilizes a ZB philosophy IIRC rather than the power scheme that most use. Additionally, Andy places an emphasis on deep RCs on much more plays than most traditional WCOs. (For example, a traditional WCO might typically run a slant/flat combo out of the I. Andy would incorporate a sluggo, corner, post, or post corner with the Z on the backside as opposed to having 2 slants).
The primary struggles IMO in trying to transition an AirRaid prospect to Andy's WCO would be the prospects accuracy (both down the field and in the short game), arm strength, and ability to sell the inside zone play and stretch play. Now, that requires A) A back worth respecting on the stretch play and B) A QB who is athletic enough to reach the 7 and sell the fake. Peyton Manning, for example isn't regarded as the best athlete in the world. However, that guy busts his ****ing ass to sell the stretch play and it looks identical to when he runs PA off it. Incidentally, the Chiefs have A) A back that can make teams respect his abilities as a runner off said stretch play, B) and OL that is athletic enough to get out and ZB and also can pass protect fairly well, and hopefully C) a QB that is athletic enough to get to the 7, can sell the stretch play and then possess enough competency to complete throws vertically and then eat up check downs once teams key on the deeper throws.
To me, Geno fits this better than any QB available in this draft by far.
As to answer your question about Andy's WCO wanting additional height/AS, I think he likes having strong armed QBs as they open up his running game after a few attempts down the field. As for height, I don't think so. IIRC, both Garcia and Vick were under 6'1 and that didn't hinder their production too greatly.