Nostalrius Begins - Quality wow vanilla realm (1.12)

From a Mage PvP perspective, do Mages get anything out of going Goblin that would be reason to not go Gnome? My Pally is a Gnome, but from a flavor standpoint, I'm having a hard time convincing myself to spec a Gnome as a Goblin Engineer.

It's an existential quandry! Any help?

First question would be for what level battleground? For leveling, twinking or at 60?

Most of the goblin/gnomish stuff I'd consider using in pvp is tradeable and usable by both such as bombs, Gnomish Rocket Boots, Gnomish Mind Control Cap, Gnomish-Net-O-Matic Projector, Gnomish Shrink Ray, Goblin Rocket Helmet and Goblin Morter.

So, let's look at what you aren't able to trade:

Gnomish: Gnomish Death Ray, Gnomish Battle Chicken, Little Smokey pet, Gnomish Alarm-O-Bot, World Enlarger,
Goblin: Pet Bombling, Goblin Dragon Gun, Goblin Bomb Dispenser

So really it's more personal preference. I have a Gnomish and a Goblin engineer so I can make everything and trade.

Right now, my Mage is 29, but I plan for him to be 60.

From a purely practical standpoint, Goblin is clearly the way to go, for the reasons you cited and the fact that my 60 Pally is a 300 Gnome and can make my Mage toys, while my Mage can make my Tankadin sapper charges.

My problem is purely lore related. How can a Gnome betray his own people's traditional technology? Arr Pee nonsense, I know, but I love Gnomes.

The phrase you're looking for is open mindedness. Your gnome is simply on yet another level of smart, he expands his horizons beyond the traditional path.

There, I solved your dilemna in 10 seconds. That will be 50g.