It’s not a problem per sé, but it would be nice that, if we introduce a new ruleset, it does not come with exceptions at conception. See the trouble we have with the regularisation of the definition of the Tuple. It hurts orthogonality.
Further, and probably this has be said before, we have come this far without a syntax for collection literals. Do we really expect that introducing it would attract a whole new poule of users? I think not. Especially not, when it starts out with exceptions to the rule.