I think it is really smart to release a belt under the HB name. It allows them to have two cars running and dial both for certain tracks. Carpet and Asphalt?
It would really be a shame if they did not continue with shaft for the Pro 5.
I think there is a lot to learn from the Barracuda and the Evo IV about bulkhead and top deck placement.
If they were to develop the Pro 4 and just make minor adjustments to it like the TC3/TC4 they have a winning car for at least 3-4 years maybe longer.
PLEASE don't get rid of shaft. Just Develope it more.