I have seen the new building going up - I also didn't realise it was opening so soon. Seems to have happened rather quickly!
So I guess this brings with it the end of the barrow crossing that has existed for so long at the station.
The main issue is that (if the diagram on Wikipedia is accurate) the Kirkgate services have to cross over the Doncaster-bound line to get onto the Leeds-bound platform to be able to get into the sidings. This must cause a bottleneck, especially during disruption.
Yes, that diagram looks accurate. What tends to happen is the services from Huddersfield terminate on the Up platform (London bound) then runs (effectively) wrong line out to the sidings with the use of a shunt signal at the Leeds end of that platform.
They then run back ECS into the Leeds bound platform, departing on the Huddersfield bound service under a main aspect, cross over to the Up line and onto the chord to Kirkgate.
I have seen them work the other way too, terminating in the Down platform and heading back out from the Up platform.
I suspect this odd arrangement allows the terminating service to come in at the same time as a Leeds bound service. Of course, when it goes wrong, this local all shacks tends to suffer