I was planning for him to climb ontop and mow things down with his Autocannon. Apparently Ogryns are mainly used to using the open topped vehicles like the Taurus, because they all naturally developed Claustrophobia, which is why they also don't ride in Valkyries.

Secondly, Ogryns are larger than Space Marines, and thirdly, Valkyries can carry Space Marines, one of the missions in the game Space Marine, is controlling Titus with a Heavy Bolter being the surrogate gunner on a Valkyrie.

[img]http://i8.photobucket.com/albums/a33/Treadhead2005/sizechart2.png[/img]