I personally think that an automated “Thanks for the suggestion” every time someone posts in the Feature Request section would be tedious and unnecessary. Now, maybe a permanent sticky post at the top of Feature Request section that pre-thanks anyone for their input and defines what they should expect from said input, would be the right way to go, imho.
The Feature Request section, as I see it, functions like a more open Suggestion Box. One that allows other users to comment (both for and against) your proposed suggestion. The back and forth by users on a request provides insight for the devs, like the suggestions popularity, or, its use case as to why it should be added (just because someone makes a request does not mean it is a good one or feasible).
I also see the Feature Request section as an informal, “Hey, I think the software should do this…”, in a discussion amongst friends rather than something heavily formalized. I realize that you are arguing for just such a formalization.
Some way of keeping like requests together. I was musing that maybe sub-sections of the Feature Request would be a way of focusing like requests together. However, people are still reading the old requests. I just got a like a couple days ago for this one from July of 2015: