To return to the original question, I'm unable to see a single reason why EMR would want Civity stock.
The issue isn't that the current stock is too low-quality; it's that there isn't enough of it. The plans for an all-170 fleet were made on the wrong assumption that Southern would somehow be able to release their 171s for conversion to 170s. It was also made on the assumption that EMR would be losing the Liverpool-Nottingham service to a different operator (TransPennine, Northern and CrossCountry were all speculated).
Which in itself is utterly dumb.
I entirely agree - but it doesn't mean they should be numbered the same!
Don't disagree, but a numbering system needs to be consistent and logical. What we have now is an utter mess.
Indeed, the Turbostar numbering has become very messy, but that seems to me to be an outlier - most of the numbering on the network at large seems pretty logical.
Why? Yet again why is EMR’s problem of having a homogenous fleet of 170’s Northern’s problem. This suggestion means pushing Northern’s average age up just as it is finally coming down. Imagine the outrage (including on this forum) if Northern replaced 2005 built class 170’s for 1988 built 156’s and 1991 built 158’s.
Why does it have to be someone's "problem"?
The fact of the matter is, there are these diagrams, these depots, and this fleet, and it somehow has to be divided between them. I can't see why it makes any operational sense to give Northern a tiny fleet of Turbostars, and EMR a tiny fleet of Sprinters, just to pull down Northern's average fleet age - an entirely meaningless statistic for the vast majority of passengers who will never encounter a Turbostar on Northern.
The railway really needs to be looking at the big picture of things, rather than having this constant race between TOCs which don't even serve the same area.