I like the idea, personally, although the "test version" is way too awkward to really be useful. Let's just propose the feature, and have these reasons replace the current "please leave a reason" popup for low-to-moderate rep users issuing downvotes, along with a "decline" option (they don't have to leave a comment). I'm not sure how it would work for upvotes though, we definitely don't want to annoy upvoters with popup dialogs.

What would be really great is if these reasons could be displayed to the poster, but optionally remain anonymous in terms of the voter. Sort of like how when I click the close link, I can see why other people have voted to close, this would allow the OP to see why people upvoted/downvoted.

I'd also prefer reasons that are a little more informative than the ones in the OP. I can't speak to SF or SU, but on SO and Meta I can think of some very common reasons for upvotes/downvotes (many of these probably apply to SO/SU as well):

Stack Overflow:

Questions:

• +1: Addresses an interesting or common problem.
• +1: Explains the problem or requirement clearly.
• +1: Well-written and engaging.
• -1: Sloppy writing, difficult to read (consider editing to improve).
• -1: Rude/abrasive language.
• -1: Leaves out critical details (consider commenting first).
• -1: Scope is unreasonably large.

Answers:

• +1: Provides correct information / working code.
• +1: I learned something new from this.
• +1: Objective, unbiased, and/or well-researched.
• +1: Offers potentially helpful advice or background.
• -1: Does not compile.
• -1: Will not produce the expected result.
• -1: Likely to fail or cause negative side-effects.
• -1: Irrelevant or off-topic.
• -1: Not specific enough to be useful.
• -1: Makes unfounded subjective claims.
• -1: Sloppy writing, difficult to read.

Meta:

Questions:

• +1: I can reproduce this (bugs).
• +1: This feature would be useful.
• +1: This is an interesting topic.
• -1: Not reproducible / not enough information.
• -1: No freehand circles.
• -1: This feature would be actively harmful.
• -1: Purpose of discussion is unclear / not focused.

Answers:

• +1: Answers the question with an existing link/feature.
• +1: Proposes a good solution/workaround.
• +1: Persuasive / makes valid points.
• -1: Unclear or unhelpful.
• -1: Overuses tired memes.
• -1: Body Odor is also status-bydesign but we still wear deodorant.
• -1: For being/agreeing with Evan Carroll.
• -1: Because I can.

Some people will probably point out that some of these overlap with close reasons. Yes, they do, but close votes are irrevocable and not everybody has sufficient rep. I also think there's sufficient gray area between, for example, rude vs. offensive, to make it a valid downvote reason. "Scope is unreasonably large" may be similar to "not a real question" but it's not quite the same. The question may be very specific in terms of the author's requirements but simply be asking for an absurd amount of work (for example somebody posting their full homework assignment).

Anyway, that's was just a quick brainstorm. Feel free to use or ignore the reasons. Personally, I think these account for 95% of my votes, and if I could click one or two buttons to add them then I would probably end up leaving more comments (especially if they were anonymous, but that's not a requirement).