Heh, solution: Don't make so many treaties.
That's certainly one option. But it's a very poor one.
The problem is that on order to do almost anything, you need to have a treaty to do it.
Oh look, your neighbor has a starving city, and you want to cash in by selling some food at highway robbery level prices. Well, we better send some right over!
- Want to send a caravan of food to your neighbor? Sign a trade agreement treaty!
- Well, I'll just send a trader instead. Better sign a passage rights treaty so the traders guards wont' get attacked by the other realm's soldiers.
- Well, I'll just send him without troops. Better sign an open borders so he doesn't just get arrested when traveling alone.
What's that, your other neighbor has some monsters that need to be vanquished, and your troops are growing bored?
- Better sign a passage rights treaty so we're allowed to move our troops through their lands.
- And while we're at it, looks like we need a peace treaty so our troops don't attack each other. Or wait, is that covered by a Passage Rights? Not sure, better sign both. Oh, and while we're at it, a mutual defense treaty to make sure our troops actually fight together.
- Oh crud, Sir Kepler's infantry got wiped out in the battle. Better sign an open borders so he doesn't get arrested on his way home while traveling alone.
- Accumulated some heavy equipment damage and want to repair before you come home, because there's a monster group that wandered into one of your own border regions along the way? Better sign a Facilities Sharing treaty, too.
These are not unreasonable scenarios for peaceful relations with your neighbors.
Anything you want to do requires a treaty. Unless you want to be a hermit realm and just sit within your own borders, ignoring the world. Peaceful relations with two bordering realms could easily suck up 8 to 10 treaties. Now contemplate going to war with one of them against a third realm. Tack on some facilities sharing treaties, a war declaration, maybe even a free-form to formalize the arrangement, and you can easily hit 14-15 treaties without even stretching.
Don't get me wrong, I like the new treaty types. The ability to control your relations to such a fine degree is very nice. But it is turning out that the amount of work required to maintain even a modest network of treaties among a small number of realms is quite burdensome. That's why I proposed some form of automated treaty maintenance, where treaties that are actually being used are either not subject to treaty friction, or accumulate friction at a much slower rate. That way the treaties that are used stay in pace, and the "fluff" treaties that are signed only as diplomatic ploys but never get used need actual maintenance by a player to keep in place.