My PCs are currently level 4 with ACs ranging from 14 (the sorcerer) to 20 (the BM fighter with plate and shield).
I haven't found to much problem in monsters hitting them.
Early on I would use more monsters that had stuff like pack tactics (Kobalds +4 to hit with advantage - challenged even the fighter).
As they go up in levels and monsters start getting +5 or more to hit - it's becoming even less of a concern.
Admittedly, my group isn't a very min-max bunch so maybe I'm just lucky. But I suspect if they were - I wouldn't have to try too hard to challenge them.
1. Athletics check to grapple, can't move.
2. Athletics check to knock prone - grant advtg & disad to hit.
3. Profit.
#3 Assumes the GM rules the prone target cannot stand while grappled (unless they first win a grapple roll), which is certainly how I'd run it.
Okay. Yes, that tactic works. But notice that you are now expecting the DM to look at two different special attacks (grapple and shove), plus the detailed "being prone" rules (which specify you can't stand from prone when your speed is 0), and put all these together to achieve a soft lock.
That goes well beyond "look at the strategies in the book."
Quick side question: Any suggestions for how to stop quoting Mort? I don't understand what is going on. Every time I try to reply to this thread, that same post is automatically included in my response.
In regards to the speed 0 idea: Something similar is currently part of what the party does. My character is a Battlemaster Fighter; one of the paladins is a Paladin of Conquest. (In the campaign world we're in, conquest isn't necessarily strictly evil... fluffwise, he's more like a paladin of the crown in service to a militaristic empire.) I'm away from books, but the general tactic we're considering, once it becomes available, is for me to use tripping attack after he activates an aura which causes a frightened opponent to have a speed of 0.
Getting back to high AC convo: Sometimes enemy spells and things which trigger saves pokes holes in defense, but that's been mostly mitigated as well. The two paladins have a good balance of physical (ST) and mental (CHA) stats on top of giving bonuses to saves based upon charisma. The heavier armored of the two (using sword and shield) also picked up a feat which means he takes no damage after making a dex save -even if an attack normally stills does half.
Thus far, our two toughest fights were one which included some type of Beholder (and the DM giving it alternate eye rays) which still did a lot of damage even when a save was made, and one which included a pack of Gnolls and the DM having miraculous rolling for the majority of the fight. Though, it should be noted that the more heavily armored PCs were unavailable during the latter; it was somewhat surprising how drastic the difference in fight outcome was without a particular class being available to the party.
On the +1 for flanking idea: It's a pretty rough idea at the moment. When I've run games in the past, I'm lenient during the first few sessions and while people are still learning, but, eventually, my general rule is that it's too late to go back and add things back in once the next turn has started involving die rolls. I'll give a little more leeway to newer players and/or if the situation is one in which character death might result from an outcome, but I also like to operate under at least some minimal expectation of keeping the game moving forward. I'll take another look at the horde rules.
Currently, my basic concept is +1 to attacks for flanking, but I'm considering allowing higher bonuses for dogpiling on an opponent. What I had in mind was something like [Flanking bonus = N/2], with N equaling the number of creatures flanking a target and rounding down fractions.
So, it would operate something like this...
nEn = n & n have a +1 bonus versus E
..n..
nEn
..n.. = +2
nnn
nEn
nnn = +4
Again, it's just a rough idea. The +1 is the basic concept. I may or may not use the growing scale, but, on some level, it makes sense to me that completely surrounding a target would make it more difficult to defend against attacks. Advantage/Disadvantage is a mechanic which works in most situations, but sometimes the binary nature of it causes what I perceive to be weird interactions in actual play. On the other hand, I can appreciate that it's easy to apply and not fiddly.