The call for such an actual prediction was based on the claim that

These predictions frequently do not overlap with what existing cognitive science would have one expect.

There is not necessarily a need for differing predictions to choose one explanation over another, which is why MWI isn't an analogous comparison. When two competing descriptions predict the exact same, you'd choose the simpler one, based on Occam's Razor.

Connection Theory, prima facie from the OP, introduces additional assumptions (additional complexity). As such, even if it reliably made the exact same predictions as previous models, it would be rejected on that additional complexity alone. Thus, CT needs to provide different and better fitting explanations than the hitherto standard, since on complexity grounds it cannot compete, unlike (purportedly) MWI.