I don’t know for sure what that person is referring to, but I believe the default in GNOME is for alt-tab to switch applications, which is a bit unintuitive. There is a simple built-in option to change it to switch by window instead, which is probably usually what one would expect. To me, that’s not something that needs “fixing”, it’s just a default to change, which is perfectly fine.
What needs fixing about Alt-Tab? I can remember not liking it but forgot why.
I don’t know for sure what that person is referring to, but I believe the default in GNOME is for alt-tab to switch applications, which is a bit unintuitive. There is a simple built-in option to change it to switch by window instead, which is probably usually what one would expect. To me, that’s not something that needs “fixing”, it’s just a default to change, which is perfectly fine.