Ok, so I'm pretty sure many players have noticed that intervention armies are pretty much... well, . The ability to prevent enemy rituals is something good, but spawning full armies at random is nonsense - and not only that, it's just lazy design. Now, I'm able to understand Chaos armies appearing out of nowhere - their gods can just send their minions through the warp portals or something. But for other factions it's just weird, and - most importantly - useless and annoying. Here's why:
1. Intervention armies are random. Which means that sometimes you can pay 10k gold and send a mediocre army into the middle of enemy territory where it won't stand a chance. Other times, you can pay the same 10k and get a force that will just rip everything to shreds - in my campaign as Clan Pestilens, High Elves decided to stop my first ritual with an intervention army with 8 Star Dragons. Eight. Star. Dragons. And some ballistas and Dragon Princes, units they couldn't produce at the time. But here's the funniest thing - even though that army could just tear me to shreds, it still failed to stop the ritual, which leads us to...
2. Intervention armies don't do their job - in my 3 campaigns so far, I have never seen an intervention army to actually stop the ritual, because - 90% of the time - they just don't even try. Every time someone spawns an intervention, it just marches off into the distance to raze some random settlements, which is annoying for both sides. The side that paid for intervention is annoyed, because they just spent 10k on an army to perform an important task, not lay siege to a fishing village in the middle of nowhere. And for the defender, it's annoying because it means every single settlement is vulnerable to a , random attack from nowhere (your safe heartlands basically turn into border provinces almost instantly) - and losing fully upgraded minor settlement can be painful.
So, we estabilished that intervention armies are done poorly, let's now think how to improve them, preferably with in-game mechanics.
1. Make every consecutive ritual take 5 or 10 more turns. It's important for the next idea.
2. Instead of spawning a random army, allow us to send our own. We already can teleport armies into quest battles, so why not do it there? Every time a ritual begins, armies of other factions could receive a new stance - Intervention Portal (or Intervention Tunnels for Skaven). An army would spend two or three turns in this stance, unable to move, but unnafected by attrition and upkeep - basically, it would imply preparations that need to be made before an entire army (or armies) is transported across the world. After set number of turns - let's say 3 - player or AI could teleport this army into regions (not provinces) where the ritual is taking place. Mechanically, it could work like, say, infinite range underway - you just click on enemy region and there you are.
3. Ok, so we're in the enemy region, but we still need to incentivize actually going for the ritual site, instead of just randomly burning local towns. Think of crusade/jihad mechanics from Medieval 2, where your soldiers deserted if you weren't going straight for your target. So here's this - every region where ritual is taking place (Hexoatl, for instance) could be given a flag, say "Ritual Region", for the duration. And in these regions, intervention armies would receive various bonuses - no upkeep, no attrition, better morale etc. However, should they leave this Ritual Region, they would immidiately suffer penalties - severely lowered morale and high attrition, to indicate that your men are not happy that you teleported them across the world and then decided to around, ignoring the looming threat.
4. So we now have an army that is focused on it's goal - stopping the ritual. If they die, they die. If they win, they can stay in the region and make sure it's not recaptured. And once ritual timer runs out, they would automatically teleport to your closest region, or your capital, or their starting point, regardless if they were succesful or not. You could also send them back before that.
That, I think, would make interventions more focused, and - most importantly - more engaging for the player. It would also enhance strategic layer - do I send my troops on an intervention and, possibly, leave my borders undefended? Do I send only a fraction of my armies and risk them being overwhelmed far away from home? Do I recall my armies in case of war, and risk my enemy retaking the ritual site? More decisions, more fun for the player.
Now, I don't think this could be modded in (then again, TW games have amazing modding community, so who knows), so I hope the devs will read that (they won't and I just wasted 10 minutes writing an essay nobody will care about, yay)
TL;DR - Stop with randomly appearing armies (except for chaos) and let me send my own troops to stop the rituals.
If you have your own opinions or ideas, feel free to share them. That way, CA will ignore all of us, instead of just me.