From a hardware perspective, juggling is better without flags and without unnecessary addressing modes.

Neither are concepts RISC-V invented, but rather, adopted. Ideas that have been plenty tested out there, and proven beneficial.

Large body of evidence trumps intuition and guesswork. Most of this is documented in the spec itself and/or in:

Computer Architecture: A Quantitative Approach (John L. Hennessy, David A. Patterson)

I just meant that it's somewhat unergonomic when dealing with the instruction set directly, FWIW. Thanks for the reference.