- It's two words and should be seperated by a dash.
- It should be plural, like contracts.
- It should be a synonym to contracts.
Update: I'm leaving this answer for better understanding, but after Jeff's explanation, I think his suggestion is better.
I disagree about the last point. I'd turn it around: contracts should be a synonym of smart-contracts. "Contracts" might get be mistaken for the meatspace usage of the word, so smart-contracts is less ambiguous.
My preferred solution is for the "smart contracts" tag to simply be removed. It's not a good tag anyways given its broad interpretation and complicated history. What would we lose by simply replacing any "smart contracts" tag with the "contracts" tag? Honestly I can't think of any disadvantage to doing that.
I was assuming "contracts" was going to be the tag and was surprised when the merge ended with "smart-contracts". I don't think there's much history being "damaged" by Ethereum's use of "smart-contracts". I'd say in this initial phase, keeping the word "smart" is helpful, as @RobertCartaino suggests.
There's also talk of potential terms such as "smart wallet" and "smart accounts" https://www.reddit.com/r/ethereum/comments/42f8qk/new_people_remember_the_difference_between_a_mist/
So unimplemented ideas in history may have to give way to actual implemented technology.