I'm sure they can find one extra 153 somewhere
You're having a laugh.
LM already have a shortage of 153's.
Could a new Birmingham - Nuneaton - Coventry service be linked into the proposed Tamworth/Nuneaton - Worcester/Herford cross city service?
The RUS talks about either Nuneaton or Leicester as possible terminuses, but I'm sure it won't be that difficault to change that to Coventry.
Winecote, Willington, Water Orton and South Wigston would still get hourly services and you could get a half hourly service at Hinkley by adding a stop on the Birmingham - Stanstead service. Only thing is that you'd still only have 2 tph Birmingham to Leicester, and you can't do couple and split at Nuneaton because the Coventry and Leicester trains use different sets of platforms.
And then there is the issue of what franchise the line will run under; LM or XC?
I'd prefer to say XC, but I've talked elsewhere about my plan for reducing the number of franchises down to 12. That would see most of LM (all minus the Snow Hill Lines) merged with the whole of EMT and the XC 170 services.
So my service pattern for the Coventry - Nuneaton line would see;
1tph Coventry - Nuneaton shuttle
1tph Coventry - Nuneaton - Birmingham - Worcester - Hereford.
Both opperated by 170's.