As briefly mentioned in #145, arrays have yet unaddressed overhead / interoperability problems:

• A compiler (or its standard library) cannot efficiently pre-allocate or resize arrays, if the language's array type is resizable (like JS), for instance by pushing to it. Instead it has to grow the array by one element at a time where the element type is not defaultable, producing copying overhead and likely garbage collector pressure over something that is otherwise the ABC of compiler development.
• Even if the element type is defaultable, resizing arrays in an efficient way implicitly makes the array non-interoperable between the module and either the host or another module because it contains placeholder elements over its actual length.

When remaining unaddressed, these limitations will effectively prevent AssemblyScript for example from adopting Wasm GC early, losing one potentially valuable source for informing the process. I hence suggest to evaluate solutions in the MVP.