It is not really something negative (because it will have to be seen in the future), but to me the biggest point about RISC-V is whether it will deliver its promise of eventually giving birth to completely open and high quality CPUs. The experiments so far are interesting and the people and firms working on it seems (to me) to be trustworthy, but the implementations so far are still lacking: the HiFive Unleashed board has a lot or proprietary IP inside and I am told that it has some stability problems. I understand and agree that things take time, but in the end we will have to see if a good and open ecosystem develops around RISC-V or not.