MTW2 can get pretty spammy w/ inquisitors and merchants swarming all over the place. Thing is dealing with them in MTW2 doesn't cost you money, just the time to groom the agents to handle them, same in Shogun 2. I can handle that.

In Rome 2 I was spending my entire treasury on dealing with this issue sometimes (not all the time), again, I'm not making this out to be a black and white issue. What I'm suggesting is I should never have 3 or 4x my imperium level limit of agents because the AI is sending an endless stream of them at me I have to kill or convert.

Set a limit to each AI in the campaign, you should no more have an unlimited supply of agent talent than you do armies, everyone complained about single city 3-4 stack armies and that got addressed, but say anything about the same single city joke of a nation sending a dozen agents at you a year and that's just fine. Really? Well how about a small dose of reality is all I'm suggesting. There should be a limit to this resource, make it two dozen. Make it the max you should get when you've maxed imperium times 2. The point is, make it something.