Prime Modifier means that every adventurer is competent in battle (both fighting and casting) without having to pay a tax to invest in it. That allows class features to shine more in terms of how and how well you do fighting or casting, and allows for any class to focus on any attribute for out of combat play. I was a skeptic when first seeing it but it really works well!

Love the long breakdown format with chat interaction to analyze the system

DC20 combat in my opinion is about the same speed of play, but much more dynamic and engaging so it feels faster!

1:13:10 At my table, we just allow the players use defensive maneuvers/reactions after the result is called, as long as they are quick about it. However, monsters/enemies can do this too.

This way of analysis on the game is very cool, gonna tune in for future livestreams for sure

A critical hit that is not also heavy or brutal, could be thought of as critical in timing/situation. The only way that nat 20 plus all the modifiers is not either heavy or brutal is when the opponent has high defense, so in that case it is critical in that you get a hit at all. So the increase damage from the critical is a nice bonus, since the opponent is likely to have damage reduction (since we know that had a high defense (either physical or mystical)).

1:18:47 Also with Parry, you’re more likely to reduce a heavy hit to a regular hit, allowing your Physical Damage Reduction to kick in

Yes, in Pathfinder second your initiative is tied to what you were doing before combat starts, so very often for Rouges stealth is used, and it is possible that for a spell caster it could be an Arcana check, especially if they were doing some sort of magical investigation when the trap is sprung

Love how you described the prime

I think that the coach's idea is that the vast majority of players are optimizing (at least to an extent) in all RPGs and therefore to be relevant in other systems, you have to optimize around the key stat for each class. So you HAVE to have your strength as high as possible in 5e, Pf2e, etc. if you want to be an effective Fighter. And when systems try and work around this and give options to be a Fighter that uses other statistics it just doesn't work as well because the core math of the game means you have to optimize the Strength above all else or you will just not be as good as other Fighters who did optimize and you won't be as good as other classes who optimized. In DC20 you can be a Fighter that chooses to be charismatic, or intelligent, or agile and they will all still be just as effective in the core of the game which is combat/challenges, since those are typically centered around the Prime modifier and not the modifier or a specific stat. Thus allowing you to build the character you want in your story and still be on par with other players at the table.

Oops... I was wrong. Don't remember where I got the idea... a conversation derived from a conversation, I guess... but Barbarians do NOT get Damage Reduction. There are also other ways to bypass it. DC's video (he has at least two channels) "Physical Damage Reduction | DC20 Game Design Insights" goes into the design of it into some depth.

I have still not gotten to play DC20, but it doesn't seem like it will be hard (based on the Actual Plays I have watched and all of the coach's videos), but he needs this feedback, since the rules as written might be in need of streamlining. Remember what most people are reading now is only an Alpha and it has only had about a year of design. For something like 5e or Pf2e there were many years of design work by far larger teams that were all done behind the scenes (and they each were built/adapted from existing systems and rule sets) before we as players knew about them. Mark Seifter has mentioned before that Pf2e was in the early design stages when 5e first came out, so sometime in late 2013/early 2014. The public announcement wasn't until 2018 and the first printing was 2019. The coach and his small team have been working on this for about 1 year.

When you talk about it should be harder to get a brutal hit on an enemy with armor, that is essentially how DC20 actually handles it. Because enemies with more armor will have a higher physical defense, the number required to beat that physical defense by 5 or more also goes up.