What race conflict you want to see more?

Murlocs vs Trolls

Oh you mean in-game? {◕ ᵥ ◕}

Goblins vs Gnomes has the potential to be quite entertaining.
With each race upping the ante, competing with each other for bolts, blasts and glory with new inventions using the most absurdly unsafe engineering.
Goblins of course, blowing things up ever more explosively and Gnomes being more cautious and spending more time on planning some of the most overcomplicated bizarre technologies on Azeroth, nevertheless, no less destructive than their Goblin counterparts.