Scheme versatility
Will Muschamp can probably be credited with introducing the phrase "being multiple," into the Longhorn football lexicon. Clearly, it's not an idea limited to Muschamp, or even the defensive side of the ball. Every offense also longs to be multiple. To that end, you could almost say that Greg Davis obsesses about being multiple, disliking bootleg plays because they eliminate one-third of the field and preferring to stay almost exclusively with his base 11 personnel (one running back, one tight end). Of course, the zone running plays Texas runs provide an argument against the multiplicity of the scheme, but that's a subject for another time.
The point in all this is that Chris Ogbonnaya provided Greg Davis with incredible scheme versatility - the ability to be multiple, catching the ball out of the backfield, picking up blitzes, even running the football occasionally. When the Longhorns went to their empty backfield look, it was almost always with Ogbonnaya split out wide as a receiver. It wasn't because Ogbonnaya possessed superior skills as a receiver when compared with actual receivers on the team; it was that the substitution patterns didn't dictate an empty backfield, as bringing in five wide receivers would. The Longhorns could still run the football with OG in that personnel grouping.
Blitz pick up
The Longhorn coaching staff preaches blitz pick up so mightily that it almost seems overemphasized. It isn't -- not when the most valuable commodity on the team is the quarterback. Protecting Colt McCoy must happen at all costs -- if McCoy goes down as he did in his freshman season, any chance at a national championship in 2009 goes down with him. Reading blitzes requires depth of knowledge, as the running back must understand the line calls from the center, while also reading the defense himself to take note of any linebackers or safeties creeping up to the line of scrimmage, indicating a possible blitz. Past the mental aspect, the running back must also have the physical tools to block an opposing linebacker -- the area Longhorn coaches are most concerned with when discussing Fozzy Whittaker, who can read blitzes well, but struggles physically matching up against college linebackies.
Hands
Coming out of the backfield, the Texas offense asks the running back to run two primary routes. Ogbonnaya's best route was the wheel route out of the backfield, taking advantage of linebackers taking a poor angle into the flat. Like the ability to plant and cut required in the zone scheme, the wheel route also requires precision, with a quick and explosive cut up field necessary when turning the corner of the wheel.
The point about hands comes into play with the next route, a basic hitch in the middle of the field. The middle of the field is the most dangerous area in which to throw the ball, as a tipped pass will often end up in the hands of a waiting linebacker or safety. A running back catching a pass on that route will often pay dearly for the four-yard gain, susceptible to middle linebackers running downhill and laying crunching hits. Despite the physical price, the running back must sacrifice their body to make the catch, the result of the aforementioned danger inherent in a tipped pass.
Vision
The zone-blocking scheme absolutely demands two attributes from the running backs employed in it -- vision and "one-cut ability." Vision is the most important, since cut-back lanes often open on the back side of plays and because the zone scheme doesn't pre-designate where the hole will open. Instead, the running back must move horizontally down the line of scrimmage, waiting for crease to present itself, leading to the next attribute. The zone scheme does not suffer running backs preferring to stand and juke defenders in the backfield. Instead, the running back must move laterally searching for a hole to develop, then immediately plant and cut upfield.