[beagle3]

I am not an expert, but my impression was always that the way it is makes things general, orthogonal, and easy to explain and reason about (if cumbersome to use).

If \left and \right were automatic, then whenever you needed something less-but-often-still common, like [0,1) open intervals, or physics <bra|ket> notation, that would require kludges.

Whether or not it is a smart decision is a different argument.

[ves]

Why not make auto-sizing the default and manual size control the exceptional case? It's already like this "in reality," I just wish the language would follow that.

I use templates so my editor shims in the above anyway, at the cost of lots of noise.