Originally Posted by
Ostrich
Gnomes carved a giant city deep inside a mountain, built the Deeprun Tram under the land and a body of water, plus they would need to dig for metal, coal, oil, etc to build and fuel their machines, so they would be confronting the elements often. Before The Lost Isles, the goblins didn't know Thrall but could still be shamans, so I don't think there's any relation. But really, the chances of Blizzard letting gnomes be shamans is next to nothing.
Honestly, as much I think gnomes should have paladins, I don't have high expectations of that ever happening either. If you want to bend the lore a bit like with Blood Elves and Tauren, it could be explained that some gnomes decided to learn more about The Light and it's purifying ways in an attempt to cleanse Gnomeregan of it's poisons and corruption, as well as become hardy defenders and healers to protect their people from the troggs.
Like I said though, as much as I think gnomes should have shamans and paladins, I don't ever expect it to happen since gnomes barely get any development and are constantly left out of the overall story, despite the fact that they are actually important members of the Alliance being the ones that build weapons and siege engines and other vehicles.