It's also about the size of an Adder, which does have a hyperdrive
The adder is 10m longer than the transporter (I think) which might not sound like much but constitutes nearly a third of the length of the latter.
With 5(6?) times the cargo (approx half that of the much larger mk III) there appears to be 5 times as much empty space in a vessel that's only 75% as big. Whilst by no means impossible such a state of affairs is at least remarkable.
So let's pretend one removes a few seats to fit a hyperdrive and be done with it.
Agreed. Minor scale issues are hardly worth worrying about in the standard game where so many exist already.
Hyperdrive has been added, testing has begun and early results are encouraging.