By my understanding of the fluff, Saurus intelligence is highly specialised - they know everything they need to know about war and anything else is the job of other subraces. A saurus mage might be plausible, but it'd be one that was literally spawned to serve as a battlemage and would probably have a lore to suit (possibly Fire, automatically changing to Beasts if mounted).
(On the topic of sauruses, here's hoping that a) any replacement of Temple Guard doesn't continue the trend of making their skull-helmets even smaller, and b) they get something like the Black Orc Armed to da Teef rule that allows them to choose between using halberd or hand weapon and shield rather than being stuck to using the former as they've been under 8ed.)
(On the topic of sauruses, here's hoping that a) any replacement of Temple Guard doesn't continue the trend of making their skull-helmets even smaller, and b) they get something like the Black Orc Armed to da Teef rule that allows them to choose between using halberd or hand weapon and shield rather than being stuck to using the former as they've been under 8ed.)