[carapace]

> Conversely, it gets easier to write outside tools that interact with Python code by removing corner cases and simplifying the grammar.

That sounds like a false economy to me. A one time small savings of developer effort (implementing the old grammar rule for decorators wasn't onerous?) to permit foolish and unnecessary intricacies among the laity.

> It means people are likely to trip over it.

Only if they are attempting to do something foolish. (Who puts whole expressions in a decorator!?)

- - - -

Tell you what, you go find examples where people have tripped over it in the past and I'll code golf them to see if I can come up with something idiomatic and simpler. Does that sound like fun to you? ("Cause it does to me. Candy!)