Just the 1960s design of that 'bus station' is enough to reject permission surely?
Unfortunately this seems to be Cardiff Council's approach to planning at the moment. If the Welsh Govt wants it or there's big money involved/to be made, a development gets the go-ahead, no matter how many objections there are.
The same thing happened on Park Place in Cathays a few weeks ago. Cardiff University want to build a new 'centre for student life' that will be built over the current student's union, which is already built over the railway. Network Rail objected becsuse it will severly restrict access to Cathays station from Park Place. Local councillors and conservation groups voiced strong objections as it will completely dominate Park Place and alter the character of the area, which is designated a 'conservation area' due to the historic civic centre character and buildings in Cathays. But it was waved through by Cardiff council anyway.
There's the same situation over in Cardiff West, where masses of new housing will be built, despite there being no rail links from the Metro into Cardiff proposed, just 'express bus routes'.