A downvote on a question generally means that the quality is low and should/can be improved.
On posts tagged feature-request, voting indicates agreement or disagreement with the proposed change
That being said, when a question is downvoted the following tooltip is displayed (I guess only for low-rep users like myself)
I think the tooltip should be changed to something different that states clearly the difference between a feature request downvote and a "normal" one.
Also I believe the tooltips displayed when hovering the up/down arrows should be changed accordingly to something like I don't agree with this proposal / I support this proposal
There's was a similar proposal a couple of years ago (Change upvote/downvote tooltip on meta sites) but it was about changing the tooltips on every question on meta and it has been rejected.
I instead propose to change the behavior only in questions tagged as feature-request, as this difference is clearly formalized in the site description.
The motivation behind this proposal is that being an experienced StackOverflow user but sort of a new user on Meta, not later than today I was very confused by the meaning of a downvote, until someone pointed me to the help center.