Sorry I am late answering!
Having come late to BTLB2, we initially had some difficulties finding some rules, as they seemed to be in different places within the rules. as we got more familiar with the system, we ironed these out!
We rapidly found this is a game we wanted to play and are essentially very happy with the rules overall!
There were several rules, however, we could not work out easily though, even using the 'What would be reasonable in reality' approach.
Obviously, the Support rule (I mentioned this elsewhere) which I believe has a error in the rule leading to 2 units of the same brigade being isolated instead of neither supported or isolated, as would be the case with a unit of another brigade being in support!
(In the same post I queried about troops going off table etc)
We could not find what triggered a 'Charge home' test (I did find this in the BTLB1 adenda sheet in the warchest...eventually!)
I had to query on this forum about 'All or Nothing' charges, as it was not clear if simply testing to charge negated any further attempt, or if you actually had to successfully execute the charge, which, I was informed, is the correct interpretation.
We had problems trying to work out which morale chart to check on when units had to test at the same time for two reasons, for example when Horse is hit by fire and loses 2 models (1/3), both causes to test according to 'Compulsory morale checks' on the quick play sheet. We worked it out eventually when we realised the Artillery test applies only to Infantry on the result chart!
These are the ones I remember. I asked my fellow players at the club if they could remember any more we had difficulty with, but they were unable to remember either! We only remember having 'discussions' about rules until someone found the relevant section!
I hope you don't mind me asking about this, I guess you are focussed on Donnybrook at the moment!
(Incidentally, as an amateur rule writer myself, I sometimes have to update my own rules as people point out errors, typos and things I thought were clear, but weren't!, and I dont especially like having to alter my 'babies' !)
PS: I am definitely not wanting BTLB3!- though I think an adenda sheet might be useful, if you agree.
Truthfully, I do worry if other people try BTLB2, they too may find the minor difficuties we have, but discard the rules instead of trying to work them out.
This is too good a set of rules to be so ignored!