“It’s probably Matt Mercer’s fault.”
Indeed. And played who are good at the improv and interaction are going to find cases where the approach they take is SO reasonable that the success/failure isn't really uncertain, just like the player who's good at tactical combat is going to work their feats and abilities that synergize with other players' abilities and spells to make combat easier.
But in both cases, when there's uncertainty, they are going to roll no matter how glib Frankie is compared Susie.
The fact is, if someone like Frankie is a lot better at those aspects of the game than Susie, if I just valued skills and adjudicated based on player skill, he IS going to be a lot more successful than Susie in uncertain situations. And that's why I don't do that and, instead, tend to rely more often on the die roll in those cases - and thus the character's assets more than the players.
We may be talking past each other if you're assuming I'm talking about the "quality of the performance." I'm not. I don't care if a character action is narrated in monotone 3rd person, or voice-acted brilliantly in 1st person. (And, to be honest, the whole voice acting thing tends to annoy the s**t out of me. Nobody I play with is as good at it as they think.).
What I'm talking about is cleverness, creativity, narrative impact. Whether it's combat, social interaction, or exploration.
And, yes, that leaves the individual judgment to the DM. My brilliant scheme may be your stupid idea. But I'd rather grant DMs that power than turn RPGs into a game of strict dice rolling.
Now, I can imagine a counterargument of "But DMs are too easily swayed by fast-talking voice actors, such that That One Guy always gets his way." Maybe some are. But that phenomenon...the DM who lets one player always get their way...shows up in lots of forms. I think the way to address that is to choose who you play with, not straitjacket the game by resolving everything with dice.
There are lots of valid ways to define "roleplaying" in an RPG, and we each choose the form that is most interesting/fun for us. I personally don't get very excited by the version that constrains me to the abilities and numbers on my character sheet. I like the cooperative games Forbidden Island and Forbidden Desert, where each player is assigned a role ("Explorer", "Messenger", "Pilot", etc.) with distinct abilities. I play those games according to the abilities on my card. But I don't think of it as "roleplaying", even if I am, in some sense, "playing the role" of an Explorer, Messenger, or Pilot.
Here's a recent post from the Shadowdark Discord:
I had an interesting experience running Shadowdark for a 5e player in my last session. I sent everyone the player quickstart before the session just in case they wanted to familiarize themselves with the game, but was super up front that I'd explain the rules during the game so they didn't need to do anything.Anyways, one player kept pulling up the rules before every turn to figure out how he'd do things, and would continuously say things like "can't do that, there are no rules for it" or "it doesn't seem I have that ability".This was even after reassuring him not to worry about things and just tell me what he wants to do and I'll tell him how to do it. Anyways I don't think he ended up enjoying the game which is fine, I just found it to be the first time I've ever had a "rules lawyer" type at my table who just couldnt let go of rigid mechanics.