Rationale
The EIP-712 specification supports fixed size and dynamic sized arrays.
From the spec,
The reference types are arrays and structs. Arrays are either fixed size or dynamic and denoted by Type[n] or Type[] respectively. Structs are references to other structs by their name. The standard supports recursive struct types.
Unfortunately go-ethereum in its current form doesn't fully comply with the EIP-712 standard because the signer module currently doesn't support encoding fixed size array datatypes.
Implementation
Are you willing to implement this feature? Yes