I actually don't mind properly done shipping.
A character must be introduced with a reason to exist BESIDES being a love interest though, that's my main criteria. Having a pony come in with no reason to be in the show BUT to be a love interest means they're one note: as such, they feel 2 dimensional.
but if they're a character with a personality and reason to appear *besides* being a love interest, they can work. It feels less forced, and can be allowed to work organically and develop slow.
Like, I enjoy Soarin dash Shipping because Soarin has a purpose in the show, and he's had screen time with dash and interaction. Likewise, I like Rarity spike because Spike has an actual personality and character interaction besides love interest reasons.