I like advantage/disadvantage quite a bit myself, but I actually didn't vote for it. In fact, I didn't vote for a number of the things I listed up there as options... but I figured someone else might see them as more critical than I do, so why not include them?"What makes D&D feel like D&D" is a different set than "what are my favorite parts of 5e". I love Advantage/Disadvantage, but if 6e didn't have it I wouldn't decry that it wasn't D&D. (I would be sad though.)
Yes but you’re still playing with a specific Class and race choice when you do that. By choosing an all Fighter campaign you are explicitly choosing to Not have spellcasting PCs - thats still a Class based gameI debated about whether to include specific lineages and classes in my vote. In the end, I decided not to. You could totally have a campaign where the only choices are barbarian, druid, or ranger and it would still be D&D. You could run a campaign with just tieflings, or no elves, and it would still feel like D&D. Heck, you could shave it down to just playing human fighters and still be playing D&D.