Isn't that how most players make their characters?
Perhaps in the world of "casual" players, it might be, but not IME. Especially for play-testing a creature, I want a character who represents what I would have actually made/played through the levels.
(Vecna is not a solo lvl 20 party threat by the numbers)
A challenge rating 26 is a Deadly encounter for a party of four 20th-level PCs. That is a solo threat IMO anyway...
Level 20 Deadly XP Threshold is 12,700 XP
Times four PCs is 50,800 XP
A single monster is a X1 multiplier (at CR 26 Vecna is worth 90,000 XP).
Since 90,000 is definitely greater than 50,800, it is a deadly encounter.
I assume that in a real-world scenario I wouldn't have known that I'd ever fight Vecna when I first made the character.
Oh, I definitely agree! I made my wizard based on the idea (as a Diviner) that his power lies in manipulating die rolls, so I took the Lucky feat to go along with Portent. Since I have no DEX, going early meant I needed Alert to give me a chance without having to rely on Portent (which is very limited at 3 times) all the time.
If you look at my spell list, much of it will have little to no impact directly (or at least not until the long run -- maybe?).
My comment was about the incompleteness I see, such as Arthur not having skill proficiencies chosen. While that might seem like a minor thing, skills like Athletics is vital for grapples and such.
FWIW, I really enjoyed your role-playing when Malek hit!