I might have missed something in the initial proposal, but who cares how attainable the "full bonus" is? Even if you could have gotten more, you'd still have gotten one, thus not much to complain about.
If the bonuses stack (as long as they cap), two battles would mean the same as one of twice the size. No way to abuse this. Also, war in BM IS a continuous cycle of refit/smash/repeat. What else do you expect in a system where you can only recruit in your capital (and repair/cash in bonds in your realm's cities, most likely to be your capital) and where moral penalties are inflicted for being away from your lands too long? It always was such a cycle, and will remain as long as recruiting in capital restrictions remain. Bonuses due to conflict don't change anything in this regards.
The rest of the issues you bring up are trivial design issues, not balance issues. The result is pretty much the same in the end, as long as you select the base factor and cap accordingly.
Let's take your example: What would happen if a small realm is under siege and has a lot of militia, if only mobile troops are counted? Let's say they have 7500 CS of militia, and 2500 CS of mobile forces in their capital, and get attacked: 100% of their mobile forces are engaged, thus, they'd get the full 1X bonus to recruitment. If militia is counted? 100% of their troops are defending the capital, so full 1X bonus again. Being a small realm with their capital under siege, they are unlikely to have militia and troops elsewhere.
Now, big realm gets attacked in a region where it has 5000CS mobile and 2500CS militia, out of a total realm-wide of 10000CS mobile and 12500CS militia. Mobile only: the realm gets .5X bonus. With militia counted, they get .25X instead. Without considering the "echo" battles on the next rounds. The big realms get screwed over, you say, because it is harder to get the full bonus? Who cares for the full bonus? They are big, even if the bonus multiplier is small, the effect is bigger than a bigger multiplier in a small realm.
And how would more recruitment slow things down?
Now, I can't say I'm convinced this mechanic would really bring anything worthwhile to the game, but I really have a hard time seeing it as overly complicated or game-breaking either.
That is because you are confusing two things. Your proposal brings in a mechanic that we might as well not waste time on implementing. It is trivial for most realms to maximize the bonus, resulting in most realms having the bonus, so nothing really changes. The complication comes in trying to design a system that is worthwhile, that provides meaningful bonuses and is not easy to game in such a way that everyone ends up at about the same level anyway.
It takes forever and a day for us to implement a change now, so something people aren't convinced is bringing something worthwhile to the game is dead before it starts. What Tom has been trying for is a mechanic that rewards realms that are in constant conflict, one that doesn't force people to fight wars in only a few different ways, that doesn't give overpowering advantages and yet provides an incentive.
