Surely any new buses will more than likely be:

Minibuses for the 46, 51 and 55, highly doubt they'll upgrade 12 year old solos (if you even can).
Deckers for the 306 maybe or the Morpeth expresses but if the Micro Streelites rumour is true Jesmond need something to replace them on the 52 and 54 and I can't imagine it being a downgrade. You also have the 3 Commanders at Blyth, Scanias at Ashington and Jesmond and B7TL's which I highly doubt will be upgraded so imagine they'll be focused on them.

No way will the X21/X22 get new buses again. The X7, X8, X9, X10, X11, 306, 308, X14, X15, X16 and X18 are all as equal importance if not more (X10, X11, 308) than them and will get new buses before them. It's stupid sending a few buses to Blyth to replace a few VDL's which will have no-where to go thereselves. I can imagine most of Blyth being renewed at the same time which won't be this year. The best thing they could do at Blyth is have an open fleet with branding for everything or nothing since nothing stays on the same route anyway (which is a good thing). Rather than X7 buses on the X10, X10 buses on the 308 and 308 buses on the X10 which happens daily.