Your personal opinions on Wargs?

[Aranwe]

the Uruk-hai were only slightly shorter than humans

The Uruk-Hai were bred to be stronger and different to other orcs - not affected by daylight etc. They were also sometimes referred to as half-orcs in the books, so they've obviously been mixed with soemthing else

The Moria orcs were a lot shorter than Men, and the orcs in the prologue were a lot shorter than the elves in the last alliance (but then elves are tall anyway...)