I seriously suggest talking to your DM. Mention the house rule in the first post of this thread. Heck, I changed that house rule to just plain vanilla "no limit on number of concentration spells cast with no additional penalties". Nobody at my table (with 5 casters out of 6 PCs in two sessions) has even attempted it yet. Explain to your DM that with the limited number of higher level spells, and the 1 minute per level duration of concentration spells, and the fact that most spells save every round anyway which quickly drop offensive concentration spells, and the fact that concentration spells can be broken easily by taking damage, you might be able to get him to allow casters to cast multiple concentration spells. That appears to be the thorn that bothers you the most as it bothered me. Heck, most melee specialists can do their special abilities over and over again whenever they want until they run out of "charges", I don't see why spell casters lose options just because they cast a spell (I don't quite see why this is the case for Channel Divinity either).
DMs should at least listen to the concern. Your DM might not change the rule, or he could change it to 2 concentration spells at a time, or 3. But this concept that the game gets suddenly broken if a PC can cast more than one concentration spell at a time is horse hockey. That's not the case at all, no matter how many people claim it is.
Game on!![]()
I don't know if I want to go that far. I don't want casters becoming uber beings at high level again. That made life hell as a DM.
I might use the house rule I proposed of limiting offensive spells with concentration by bonus action with one active defensive/utility spell. I think even Domination requires an action or bonus action to give commands. I think that would create a sufficient limitation on concentration to ensure buff stacking was still very limited, while allowing a wizard more offensive options. I don't like the idea of a 1/4 to a 1/3 of the spell list eliminated after you cast a single concentration spell. I don't want to see an insane amount of stacking either given the creatures are built with limited stacking in mind.
No limits on concentration would allow multiple casters to stack a ton of buffs making encounters trivial. I don't want that. I also don't want such a tight limitation on concentration that your forced to choose between buffing the party or using fun spells to attack the creature.