How would a house-rule allowing the Wild Magic Surge sorcerer feature to work with cantrips as well affect its power level?

Question

I’m preparing to run a 5e campaign, and want to make a change to the Wild Magic sorcerer's Wild Magic Surge feature (PHB, p. 103). Instead of the description saying:

Immediately after you cast a sorcerer spell of 1st level or higher...

I would like it to also work with cantrips, reading:

Immediately after you cast a sorcerer spell...

How would this affect balance?

Bonus: I’m running the Lost Mine of Phandelver Starter Set adventure, so any extra information relevant to that adventure (and the question) will be appreciated.

Answer 1

It wouldn't

Honestly, in my table experience with Wild Magic Sorcerers, the surges are so few and far between that it's a bit frustrating and sad.

It's the surge that's fun (and that resets some of the abilities) and from what I've experienced, anything that produces more surges makes it more interesting.

By increasing the volume of Wild Magic rolls, you are inherently increasing the odds that you'll get one. While the DM can always ask for one under their own circumstances, providing a set mechanic I think makes the class more fun and playable.

Until they set off a fireball centered on themselves.

Answer 2

This is more unbalancing than you think

I've played a WM Sorcerer a couple times and it is pretty fun. I relied upon some guides to build a character that was optimized and in general, WM works best away from the party. In general, one of the restrictions on WM is that you cannot reliably use it outside of combat and this proposal would change that. One of the key things to take away from the surge table is the following (from Cognomen's Cassowary's guide):

There it is, the entire table broken down for easy digestion. To tally, there are seven gold ratings (14%), things you are happy to have virtually any time they come up. There are eight light blues (16%), signifying effects that are less powerful but you're still happy to have. There are six solid blues (12%), mostly ancillary effects and oddities which are on the whole positive. 42% of the table is definitively positive.

There are two green results (4%) which are slightly positive, nine (18%) which are RP centric, and three (6%) which depend on how the DM plays them. (Two of them summon creatures within five feet of you, so you might actually be able to use them for cover.) 28% of the table runs neutral to slightly positive.

Three purples (6%) represent results which are negative on balance but might have some useful attributes, and three reds (6%) comprise the worst, outcomes with no redeeming value. 12% negative effects move the total to 82%. What about the other 18%?

What remains are the situationally good or bad results, six of which (12%) are better if you're near enemies and three (6%) near allies (including self-centered fog cloud, which is something of an edge case). This is important for understanding how to optimize your play. If you are near (for most effects, within thirty feet of) your enemies but not your allies, you push the number of positive outcomes up to 54%, while increasing the negative to only 18%.

Outside of combat, your proposed house rule would permit players to effectively abuse cantrips to force a surge whenever they want. In general, this will most likely be good for the player; the exact nature of how it's good will be variable, but there are several things on the table that can come up which permit a sorcerer to fully recover their resources:

• For the next minute, you regain 5 hit points at the start of each of your turns
• You regain 2d10 hit poins
• You regain your lowest level expended spell slot
• You regain all expended sorcery points

This is only 4 out of 50 possibilities on the table, but a lot of the table possibilities aren't negative provided the party gives the WM Sorcerer space, so more often than not the party will come out ahead. As this house rule let's them persistently try indefinitely, there's nothing but notably bad luck preventing them from fire bolting a wall until they manage to recover all their hit points/spell slots/sorcery points.

This would substantially worsen when the WM Sorcerer reaches 14th and gains Controlled Chaos. Since you're doing LMoP, that's a bit out of reach, but the impact on the long game is worth noting.

The built-in means to deal with the issue of infrequent surges is the Tides of Chaos class feature. As a whole, WM Sorcerers fully come on-line at 2nd level when they gain that feature.

The querent has stated they are the DM and would indicate when they want surges to occur, but I would recommend taking an opposite tact. Indicate when you don't want them to occur because you will forget and it will be annoying from the player's perspective every time you do. As a DM, you've too much to keep track of as is and every time you forget to ask for a surge is a chance that player doesn't get to use their class feature that every other sorcerer origin gets to enjoy by default. Let the player keep track of when to roll for surges on their own, including with Tides of Chaos recharge and you will find that surges happen pretty regularly, which is what should happen.

If after seeing the results of play through 5 levels by letting the player control their surges, I think you'll find the surges happen more than enough on their own.

Answer 3

The Tides of Chaos feature seems like the best way to increase their frequency, and probably the most balanced and tested.

In my experience, especially at lower levels, the Wild Magic surge results can swing situations pretty dramatically, and in unexpected ways. If you're running a wacky campaign where you and your players are ok with that kind of thing happening frequently, then go for it.

However, if things are meant to be more serious/predictable, then I think it could impact the tone and pace of the game.

Further, having it tied to a cantrip would let players potentially abuse it, by just casting whichever cantrip they have until they get the desired result on the table, which could really sideline the game if it's allowed.

Another thing I would consider is how it would affect player highlighting, for lack of a better word. In an ideal situation, every player/character has an equal time in the spotlight during game, but if one of them is constantly shooting lightning, flying, turning into sheep, and becoming immortal, you could see how that might sideline other characters.

Personally, if you want more surges, I would just discuss it with your player, and come up with a system that involves some middle ground. Roll a die behind the screen, and after they've cast that many spells (of any level), have them check if they surge? Or just roll on the table? Increase the chances of the surge happening when they're low on HP, or in a desperate situation? Or, make the surges more common as they increase in level? (1/2 level or something, instead of just a 1 on the d20?) You could also just say that you can call for the roll on ANY spell, rather than just 1st level or higher, and then do so as you feel it is thematically appropriate.

Answer 4

What bothered me in playing a Wild Magic sorcerer whose backstory has their magic out of control but building up the more magic he uses(or conversely his resistance to it goes down) is that I could cast cantrips till the cows came home with no chance of a surge. It just doesn't seem right or sensible. At this level 2 I am finding cantrips very effective and so far see little need to dip into level spells. The idea the DM and I are discussing is rolling a chance for a surge after so many cantrips, say 10. I also like the idea mentioned here that chances go up under combat stress - which would match my personality as well. I admit I have not yet fully gotten my head around Tides of Chaos so maybe that is another way to scratch my itch.