What nonsense.
It is absolutely incorrect that you have to 'keep Vim in your head just as much as the code that you're editing' unless you have not learned Vim at all. The reason you don't (constantly) have to think in ST or notepad++ is because you have already learned that editing paradigm. Although, that editing paradigm IS more obtrusive than vim's. It's abundantly clear that you do NOT understand vim's keybindings and modal editing concept, if you constantly think about vim.
vim has code exploration tools integrated: they just have funny names like ctags, grep, cscope. If you want them. You can also just use separate tools for browsing vs. editing, with no obvious productivity loss.
The productivity impact of having the debugger in your editor process cannot be a big deal, and it's pretty weird to hear that this is essential right after you stress that notepad++ is good enough. Which one is it?
If the point is that you spend most of your time writing, editing and reading code and otherwise the only advantages are in heavy-duty tools not present in ST, then the implication isn't that it's "sane" to reject vim, the implication is that it doesn't make any difference what you use.