The 6502 is designed to be a simple, minimal, low-cost CPU. From that perspective, it's a brilliant design, and it's fun to write small programs for.

Where it becomes "deeply flawed" is if you're trying to develop large, complex programs for it, mainly because there's no way to efficiently implement pointers or local variables -- you only have 3 registers, none of which are truly "general purpose", and none of which are wide enough to hold a pointer; and stack operations are severely limited. (This also means that writing a C compiler that targets 6502 and generates efficient code is almost impossible).

So, in idiomatic 6502 code, all variables are global; and if you need dynamically managed objects, you keep track of them using indices into statically-allocated arrays. This is difficult to scale as your programs get large and complex, because at some point you're going to waste an afternoon finding out that your "tmp7" variable in one routine is getting clobbered by another routine 5 levels deep down the call chain that also uses "tmp7" for some unrelated purpose.

It was a perfect processor for its time and its target market, but it made heavy design compromises to achieve its goals, and Moore's law quickly made those compromises obsolete.

>Moore's law quickly made those compromises obsolete.

Your overall argument is perfect, but I'd question the use of "quickly" since people were selling essentially 6502-based stuff for how long, 20 years at least? From the Apple II in 1977 to the SNES which was released in 1990 and still getting games in 1995, so that's 18 years of that CPU being highly relevant and worth learning.

Of course, you're 100% right that, assuming money was no object and you could buy and use whatever hardware you wanted to, it wasn't long before you could escape those compromises since the x86 and the 68000 (and probably others I don't know) brought much better architectures to those who could afford them.

It's not "deeply flawed" at all, OP is being overly dramatic with that statement.

I've coded on a bunch of embedded 8-bit platforms over the decades, and 6502 is great. A, X, Y registers - it's really quite simple. It has various standard and useful addressing modes. It has pretty much the same status register that exist in modern 8-bit MCUs. There's nothing "deeply flawed" about it.

32-bit MCUs are probably a bit too complex for a beginner, 8-bit MCUs will teach a newcomer a lot about the basics of computing in an easy to learn way. It will teach them the significance of "a byte" and working with raw data that maybe you don't exactly get with 32-bit MCUs. There isn't that much to master with a 6502, it's pretty simple, but amazing things can still be done with it.