If your DM is throwing casters at you that would fail a DC10 Concentration check, you've gotta be sub-2nd level. ๐
At 14 con (which is a reasonable to high con for a caster), there's a 35% chance to fail this check. Even with advantage (e.g. war caster), there's about a 12% chance.
If your DM consistently sends casters with higher con saves, he just really doesn't want you to ever break it.
And that's coming from someone that has a cloud giant wizard with a +10 con saves as the BBEG last session.
I mean, at that point just don't roll con saves for them. Special NPC magic (tm).
I think I'd build my caster's to have low enough Constitutions that they probably would have a 50/50 or similar. If someone is focusing on attacking the caster, I want to reward them by making the chance to end the concentration high.
Besides, for most games I've played, I recon right up into tier 3, most damage still comes in at under 20 per attack, so it's still a DC 10 save.
Wait. You do sub-20 dmg at Tier III? Your DM is letting you bowl with bumpers on.
I ran a 1-17 game and typically as a DM I wasn't consistently dealing over 20 damage per attack until I was using CR 13 or greater monsters or higher, and I'd typically prefer several monsters per encounter to one, so that probably happened consistently around the time the party were level 12 ish, and even beyond that, I would say I generally didn't focus on massive damage output because knocking PCs out the fight in 1-2 rounds doesn't give them enough time to assess the battle and then deprives them of agency through a particularly slow segment of the game.
I'm currently a player, playing a trickery cleric 9 rogue 2 and loving it, but I think I use my 4th or 5th level spell slots for a damaging spell about once every 5 encounters, because those spell slots are better for exciting spells like polymorph, scrying or modify memory, or at least I find those more exciting than making my number go high. In that game, the paladin 6 bard 5 may on occasion do a spike of damage via a smite but his spellcasting is also primarily utility too, and our only massive damage dealer is our draconic sorcerer. A lot of our consistent damage comes from our barbarian who is probably putting out 40 damage per round but rarely over 20 in a hit when not critting.
As players, if we want to knock an enemy out of concentration, we're more likely to pepper them with small secondary attacks, forcing them to make 3+ DC 10 saving throws per round, which has generally been more successful than one 30 damage attack and a one DC 15 save, just because of how the odds fall.
According to Matt Colville, and I'm paraphrasing here, "Your monsters should be doing average damage equal to 6, + 3 times their CR". Therefore, your < CR 13 monsters were so nerfed that their actual CR was less than half (+/-) the printed number. All due respect, but if you're training your players to interact with the game system in this manner, you're not only making more work for yourself, but you're setting them up for a rude fucking awakening at nearly any other table than yours. ๐คท๐ผโโ๏ธ
Looking back at some of the monsters I used, which were generally official monsters or from tome of beasts 1 or 2, they traditionally were dealing about 84 damage per round if it hit all attacks but only 21 per attack. I remember using an adult white dragon (CR 13) while the players were about level 10. That's going to either use it's breath (54 but 22 on a save), or any other combo of attacks that wouldn't deal over 20 withousome lucky dice rolls, averaging 13-17 damage per attack, and 58 damage if it uses its legendary action to use it's tail once and hits every attack.
Also my table sounds like a different experience to yours. All the players are people I'm friends with in person and as we've become more experienced with RPGs, were played different games rather than optimising 5e, and we tend towards storytelling focused RPGs like Fate or collaborative storytelling games like For The Queen. If we are looking for difficulty, we're likely to seek a full horror experience over 5e. I enjoy the content Matt Colville but I know his style isn't for me, it's very tactical and all about combat, while when I play 5e, I find combat often becomes a necessary chore that the system is built around that only engaged each player half the time and takes far too long to warrant the storytelling it provides.
Ironically enough, I generally can barely stand D&D these days, and much prefer systems like Blades In The Dark, Powered By The Apocalypse, Ironsworn/Starforged, etc., so please understand that while my criticism comes from a place of cited reference, in no way do I support the tactical "storytelling" that WotC sells to the unwitting and the brand-loyal. In fact, it seems that we're of very similar mind, after all. ๐คโค๏ธ
edit: I'd like to point out that I had the "privilege" of playing in a game that Gygax ran at GenCon back in the day, and Colville's "style" is cut from similar cloth. Some might enjoy it, but I genuinely wish the flyleaves of rulebooks still assured readers that the book's contents were merely guidelines to assist imagination among their group.
I'm finding this way funnier than I should, thanks
As a DM I would explicitly make the Concentration DC vs Vicious Mockery higher than normal.
begins laughing at the enemy sorcerer
"What is that? It looks like a wand, but smaller!"
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