Multiclassing/Dipping Shame

[Max_Killjoy]

Well, the latter is not something classed systems (even D&D) say, so that's not really a good example. But ultimately, you're not really rebutting the point. It's certainly possible to make claims that violate suspension of disbelief, but you're never going to be able to draw a bright line and say "this right here is the point where you've bundled abilities together too much".

I am taking these examples straight from the 5e PHB, so don't sit there and tell me that it's "not something classed systems do".

You're trying very hard to elide the clear distinction between "being smart makes you better at doing X", which is no different from "being strong makes you better at lifting things"... and "here's are two unrelated abilities we've decided you have to take both of in order to get either of".

And again, it's not about suspension of disbelief, it's about the relationship or lack thereof between the abilities, and the way the abilities in a class are divorced from specific characters and instead require the player to choose a mechanical package first and then build the character (as in the "fictional person") around that grabbag of unrelated abilities.