Yes from a design philosophy standpoint vis is closer to kakoune than {neo,}vim. The implementation is quite different though (no C++, no boost, no home grown scripting/extension/syntax highlighting language).
I don't use either, but to be fair, I wouldn't call vis's requirements lighter than kakoune. Vis needs Lua and libtermkey (which according to its author is EOL'ed) at build and run time.
Regarding vis, Lua is optional (you lose syntax highlighting though).
libtermkey is a 3 file library and despite what the author claims it works, is useful and could be maintained in the vis repository if necessary.
If you think anything C++ related is lighter than something C based, then we just have to agree to disagree.
Dunno about libtermkey but I wouldn't worry too much about the Lua dependency. Lua is very portable and lightweight and the entire Lua interpreter and standard library are just a couple hundred kbs. You always have the option of linking them statically if you really need to.
