Well the parentheses seemed like a reasonable way out of this mess - by APL2 standards I'm not sure they are redundant:
I know Dyalog allows:
a b c←5
but in APL2 you would need to specify the assignment as:
(a b c)←5
The parentheses are not redundant -- a notation I much prefer, but I see your point in this case.
I guess my point is if we are carrying on with the original 50-year old mistake of treating a 1-element vector the same as a scalar, then it should hold true for the dot notation as well or we should dispense with it here. As the language advances, this original gaff becomes bigger and more difficult to program around: