Cantrips gain potency at higher levels. They don't specify the class. The thing that allows multiclass characters to gain the bonus before reaching those class levels is the part in the multiclass rules that specify it.
There is no such rule for feats.
I appreciate your thoughts and contributions here, Ad Hoc. For clarification, when you write, "The thing that allows multiclass characters to gain the bonus before reaching those class levels is the part in the multiclass rules that specify it," are you referencing this from page 44 of the 2024 PHB (which, I believe, is identical to the 2014 rule): "If a cantrip of yours increases in power at higher levels, the increase is based on your total character level, not your level in a particular class, unless the spell says otherwise"?
I think I understand your thinking and the basis for your interpretation.
I think this one is a great question for Jeremy Crawford and Sage Advice as it is perplexing.
Reasons to Interpret that at 19th total character level (example, a level 15/4 character taking an Epic Boon Feat) one can take the Epic Boon Feat:
- D&D Beyond permits it when it otherwise does not permit rules variations or homebrew without stamping a character as made in this way (Chaltab). The problem with this is that it is suggestive, not authoritative because D&D Beyond is an application/program.
- "Abilities that require a certain level in a class specify it. For example, the warlock powers that require a certain level don't say level 5+, they say level 5+ warlock" (Mort). The important corollary with this is that on page 210-211 in the 2024 PHB, all of the Epic Boon Feats specify "Prerequisite: Level 19+" not "Class Level 19+." Related to, and supporting this, is John L's observation that Elf Traits specify "character level" but the Elf Lineages table on page 190 shortens this to "Level."
- The wording in each of the 12 "Class Features" sections specifies the class level for Ability Score Improvements/Feats but the class level is not specified for the Epic Boon at Level 19 (John Lloyd). But, we should not forget that the ability to acquire an Epic Boon Feat at Level 19 always occurs within the context of a class Features table and text explaining class Features; therefore, one could argue that it is implied that Level 19 must be a character's class level.
Reasons to Interpret that only at 19th class level one can take the Epic Boon Feat (meaning any character with more than. a 1-level dip in another class would have to wait until 21st-level to acquire an Epic Boon Feat):
- The acquisition of the ability to acquire an Epic Boon Feat only occurs within the context of the table and text explaining class Features (Clint L).
- The Multiclassing rules on 44-45 of the 2024 PHB do not address whether Epic Boon Feats use total character level or class level, and this would be the place where it would be addressed if it was total character level (Ad Hoc).
- Ad Hoc's aesthetic objection that if 19th level is interpreted as total character level, then some multiclassed characters might never acquire an Epic Boon Feat and a 15/4 level character advancing to 16/20 would actually acquire two Epic Boon Feats. Of course, some might counter that this is not game-breaking and is reasonable compensation for a multiclass character missing out on a 20th-level capstone Feature.
In reading everyone's contributions here and thinking about it, I am stumped.
Aesthetically, the more I think about it, I am actually finding myself in very much the opposite position of Ad Hoc. Missing out on capstone Features is a big sacrifice for high-level characters (or, in my case, I frequently make NPCs as if they were PCs). So, acquiring an Epic Boon Feat (or two in the 15/4 character example advancing to 16/4) is nice for those characters; I would even regard it (at this point) as an improvement over 2014 multiclassing. I do not think it is game breaking.
Further, in looking at Class Features for level 4 characters, there is never an advancement in spell level casting at level 4, nor is there an advancement in spell level casting in the Multiclass Spellcasting table on page 44 of the 2024 PHB, meaning most spellcasters simply receive one additional spell slot at that level; so a multiclassed 15/4 character receiving an Epic Boon or a 16/4 character receiving a second Epic Boon, are not really gaining much from their class level progressions at that point. Further, class Features are minimal for all the classes at that level. So, why not receive even a second Epic Boon?
But that opinion does not pertain to the interpretation of the rules, which seem ambiguous.