Yeah, I'm blaming the players who filled out the surveys if they downvoted the half-caster warlock because they just didn't like this particular version of it. Those people apparently never learned or understood how these surveys worked for WotC, and/or were unwilling to "play the game" as it were. Especially if they also didn't fill out the write-in fields saying they liked the idea but wanted to see iteration before giving a full thumbs-up.
If (general) you were a person who loved the idea of a half-caster warlock (or templated wildshapes as another example) but still gave them 1s and 2s because what WotC offered up wasn't 100% the way you'd prefer them to be... (general) you pretty much shot off your own foot. The lesson was to give the new idea a 5-point double-thumbs-up first... then write in the fields some of the changes that you thought the idea could do with to be even better.
Apparently not enough people figured that out.