That's a long rant, haven't got to the end yet. But when at the beginning I read about sticks of 6 NiMH batteries in series, I said to myself, "uh oh".
Basically, that is a huge design failure. You can't design durable, long life systems with sticks of NiMH batteries in series, and then hope the system will last. If you do that, you are screwed.
Given a series pack of NiMH cells, one of the cells will be weaker than the others, and at some point during deep discharge it will suffer a polarity reversal. Once that happens it will get weaker and weaker until the whole pack fails to perform.
You can mitigate this problem by careful selection and matching of cells before assembly, by avoiding deep discharge, and by period maintenance charges.
The maintenance charge involves running a timed C/10 charge for 16 hours to re-balance the pack. This should be done after about every 10 normal discharge cycles.
The question is, when is this battery maintenance going to happen while the battery pack is buried in the middle of a vehicle? It basically isn't.
So when NiMH batteries are installed in a car, you will experience the normal and expected lifetime of 2-3 years until replacement, and then the battery pack will reach end of life. This is true of NiMH batteries used in other applications, and cars are not special. Probably, cars are a more hostile environment than many others.
In short, if you see hybrid vehicles with NiMH battery technology, run away. Run away fast.