I’m not saying don’t do this, your vimrc is your vimrc, and who am i to say “dont’ change the defaults”… but I once went down the road of changing frequently used, common defaults and really regretted it later. one reason was that i needed to use embedded vims elsewhere and I could no longer use my muscle memory. I was often enough that it was quite annoying and so i went back to defaults and wondered why i even changed them in the first place. the defaults i changed weren’t “less efficient” or “harder” or some damn thing, i just suck at typing.
however if you do go down this route i would suggest that they still fit the mental model of hjkl i.e. horizontal/vertical. next blank lines (or scope or function) for the vertical movement on j and k, beginning end of line for h and l, would be an example. overloading hjkl and its shift, alt, control modifiers is fairly nice when they all share the same mental model.