1) Divination/Augury/Commune: Every time this spell is cast on the same subject per day, there is a 25% cumulative chance that you get no answer.
So the key change is this no longer applies to just a person casting, but EVERYONE. This means if you cast divination on a subject, and then ask your neighbor to cast, the cumulative chance adds up. This is so that divinations are still present but a little reigned in. I can sometimes let them work, sometimes that topic is so commonly divined that you don't get an answer. And it prevents a group of 5 wizards to just divination bomb a particular problem.
I think I'd just make any answer to repeat questions the same already. Conceptually, the spells are contacting deities, and those deities are telling their subject what they know. Deity A and Deity B are probably likely to know the same things unless they're diametrically opposed or something else strange is going on where one deity has special knowledge or interest. Unless I had a good reason to think otherwise, I would default to assuming that the answers would be identical. I wouldn't even tell the players this information unless they got really obnoxious.
2) Gate: Effects that block divinations prevent a gate from pulling in a creature.
This is to give my big bads a little plot protection. Normally once a party learned a bad guys name, it would simply be a matter of getting a gate requested and then arresting or destroying the target at their convienence (again the city wouldn't do that willy nilly, but for a nasty notorius bad guy why wouldn't use cast such a spell). So this gives a few ways to counteract that.
I don't think I've ever been worried about Gate. Firstly because I can count on one hand how often my PCs have gotten the spell at all, and second because I don't think I've ever challenged the party with something that wouldn't have some sort of magical protection, be it a Forbiddance spell, a magic item, etc. Alternately, you can simply rule that the character is using a pseudonym or code name.
Like it doesn't matter why. It doesn't work because it would be stupid if it worked. "No, the giant eagles will not fly you to Mt. Doom."
3) Modify Memory: If the spell is cast 3 times on the same subject and involving the same memory, the effect because instantaneous and can't be removed.
One of the things about being an agent in such a powerful city, is you would expect them from time to time to get a routine remove curse/greater restoration cast on them. Especially a remove curse, it would be like getting your annual check up. So I want to ensure certain spells like modify memory can still hold up...but it takes some real effort to do it.
I guess? I mean, it doesn't arguably work on anyone immune to Charm, it certainly doesn't work on anybody who isn't completely alone, and it only works on things that take 1 minute to describe. This spell's best counter is literally having a friend or a guard with you.
4) Geas: The damage is 5d10 psychic damage + 2 fatigue, and it occurs every time you violate the act (not just once per day). In order to remove a geas, you must cast a spell at a higher level than the geas was cast. When the geas is removed, you immediately take the damage one more time.
At higher levels, Geas adds +2d10 damage per level increased.
I like Geas, but I really want it to hurt. If you have a Geas as a medium to high level character, you are seriously going to think about it, as opposed to just "oh a little damage, cleric heal me up I am good for the day". So this is meant to be a very strong buff to what I think is a cool plot spell.
I agree, Geas is a pretty poor compulsion. A previous DM I played under had a subject that disobeyed suffer as though they had incurable Sewer Plague. At the end of any long rest if the subject did not work or intend to complete the assigned task since the last long rest (or in the last 24 hours), they suffer an additional level of exhaustion (similar to failing your save against the disease).
In other words: "A disobedient creature suffers one level of Exhaustion, and it regains only half the normal number of Hit Points from spending Hit Dice and no Hit Points from finishing a Long Rest. At the end of each Long Rest, a creature that has continued to be disobedient gains one level of Exhaustion to a maximum Exhaustion of level 4." I think it was level 4 maximum. I know he made it so it couldn't possibly kill you. He also ruled that impossible tasks or tasks that the subject doesn't understand (in spite of knowing the words of the task) work the same as a suicidal task: the spell ends.
The core problem with the spell is that it's built to deny agency, and that's not really very fun for the target of the spell at all. I think the spell is so weak so that DMs won't be tempted to use it to compel players to do what the DM wants.
5) Dispel Magic: A dispel magic check automatically fails against a spell 3 or more levels higher than the dispel.
This is actually an issue I have from my previous campaigns as well. It is way too easy for mid level parties to dispel any magic effect that have with enough casts. "There is a tomb protected by a 9th level effect!" "No problem, just give me a few casts of dispel and we will take care of it".
I don't mind dispels going a little above their pay grade, but the idea that a base dispel from a 5th level character can take out 9th level spells from a 20th level one is just a bit too much for me.
I haven't really encountered this problem. Most powerful magical effects aren't spells that the players would notice, and few of my players would attempt to use dispel to break them. I would simply say, "A caster who fails their check to dispel a given effect cannot attempt to dispel the same magical effect for 24 hours."
6) Counterspell: Removed
There are a lot of comments on the boards about counterspell and its power. At the end of day, I just find it unfun. Its unfun when the few spellcasters I run get neutered by one of the party, because I get maybe 3 rounds in a 5e combat and one of them is a waste of time. Its unfun for the players when they see an enemy wizard and know that one of them is going to lose their turn due to counterspell.
I think the game gains more than it loses by the removal of this spell.
It's never been a problem at our tables, but if I were going to change it I would just remove the "At Higher Levels" clause. I might consider changing the DC to 13 + the spell's level.
I know one DM who changed it to only work on spells of 3rd level or lower, kind of like a one shot globe of invulnerability. It's fairly narrow at that point, but not useless.
