You obviously have been in Germany for a long time. For me, muss and dass are ok. In my opinion, the rule now makes sense. Less need to learn by heart. Books with old spellings are difficult to read. But those who are used to the old spelling, of course, do not perceive the new well. Changes in language and spelling are always met with hostility in all countries, so they are rarely carried out and not always completely successful, because they try to please everyone. In my opinion, there are much less successful innovations, such as the new written multiplication in Germany.

Words like “Schiffahrt” were changed to “Schifffahrt” after the reform. “Flußschiff” became “Flussschiff”, and so on. Street signs were even changed to reflect the new spellings! Phrases that had been separate by the old way of spelling (zur Zeit) became joined in the new (zurzeit), while words like “zuhause” were separated into “zu Hause”.

After all these years, spellings like “dass”, “muss” and “wusste” still look odd… !