You explored 5 provinces by 50-100%, protector. Why would you make a disingenuous argument about those numbers? I can see why you would decline their cf offer though, as they were close to giving button and might have (or might still) given you another farmwar. We did the same against Chrystal last age. The possibility of gaining 20k in a min time war far outweighs the damage done by a ghetto limited to one hit a day.
As I see it we were probably going to decline BB's mediocre cf offer, and would have fought them. The war would (IMO) have been 50-50, with us having more acres/troops and them having a better spread and cleric bonus. After the razing idiocy, we knew we couldn't push any sort of advantage and took a cf offer that was still quite advantageous for BB (again IMO). BB's original offer was yr2, which would have let them use more pool than us and would have put us at worse than 50-50 odds; the offer they finally made was yr4 which is probably back to 50-50.
Everyone will agree postwar is overpowered, but I don't think hitting into it unprovoked is the answer. In most cases you have a notice deal with kingdoms in range of you - which is basically necessary, otherwise anyone leaving postwar can destroy you since they not only can be more pumped but can completely control the timing of the fight. I don't have a good answer for this, as it's part of the overall problems with the current mechanics that force fights to occur at superpump levels all the time where a small difference in the timing or pump level of the fight often determines the winner. One thing I would suggest though is that notice should be allowed into/from postwar in future CF clauses, as the war winning kingdom should still have the advantage even if they "only" have 4 days to prep instead of 6-7. Yes, this is off topic.