Change your shell now and test - no need to wait.
chsh -s /bin/zsh
All the scripts that depend on bash syntax will still find and call bash. Also, I would estimate 95% of macOS users don't use a command line and of those that do, another 95% won't have to change anything significant or at all. (I'd wager it's more like 10% of the 1% that know shells exist need to do anything other than port a couple lines in their .dot files)
Your prompt will change and if you changed your prompt on bash, the way to change it on zsh is no harder and no less documented than bash.
The newer shells would fail to ever get off the ground if they broke major items or caused a painful adaptation period. If you want a more fundamental change and really want a shell you need to think about and requires training and intention to adopt - try [fish][1].