I disagree. Sometimes you might select such combinations because you like suboptimal combinations for a challenge or for other reasons. (The rules should not prohibit from making such selections.) However, there might sometimes be advantages as well as disadvantages to your selections.

However, I don't like class-based systems so much, and I prefer skill-based systems. Instead of selecting a character class, you can select which skills you want (including narrower skills; I think the skills in GURPS are not narrow enough) and how much of each one.

But see also my other comment for other details.