Regardless of motivation, “I have considered vim and emacs and they’re not what I want” is a valid preference and I think we should avoid challenging it. I don’t think we’re helping by suggesting variants of vim and emacs here – and I say that as someone who would recommend vim over pretty much everything else out there 
That said – I don’t know of any editors that meet the criteria posted, so I’m at a loss. If you were on Mac, I would have a couple other suggestions (but even these might violate your “open source” requirement), but for Linux? I’m hard-pressed to think of anything.