My main reason for two separate banks is redundancy. I came to sailing through aviation (hang gliding) and have grown to respect redundancy. I also thought, to extend range it would be nice to be able to charge one bank with a portable generator while using the other bank for propulsion. In real life (so far) I've never had to do that.
I understand the Peurket Effect dictates a bigger bank will provide more available amp hours but from what I have read at the rate of current draw that I use it's not that big of a factor. In the past I have had an issue with a battery that started to go bad in one bank and while I sorted that out I had a good bank to keep me sailing.
The PakTrakr monitor does give me amp draw among other helpful information to keep my batteries healthy (that's how I found the weakening battery). You are right that knowing amp draw is absolutely necessary. The most I have seen as far as regeneration is concerned is 4 amps at 48 volts.
I have a tight slip that gets some significant surge at times and having my boat walk to starboard is helpful. That said I will be installing the CS at some point.
Thanks for your interest, Mark