This is where moderation comes in. They did this kind of interaction for years without issue. People can have their controversy and the devs don't need to pay attention to it at all quite frankly, it's a fairly isolated area for such things. The community managers simply notice things they feel are worth passing on, highlight them to the devs, and we get the odd response. There is no obligation for them to say anything beyond that. If they're going to have these forums, they absolutely can work. They did it in the past, there is precedent for it working absolutely without problem. Only in the past two years have they stopped doing it, and I dare say that the forums are worse off for it, not better.
Regarding the post by kaynide, the things they tended to reply to in the past were always well written and I don't think they ever really had the impact you are stating. I've never seen a mod or dev say they don't like an idea. They only posted about things such as:
1) Reasons why something can't be done (not to say it isn't a good idea)
2) That something is a good idea and they will look into it
3) That they agree and a fix has been implemented
4) Providing lore details
Of course, I've not seen every single post by the devs and community managers but I don't recall any time they caused any problems.
EDIT2: Examples of how mods/devs interacted with the community in the past:
Help/information provided for a user
https://forum.square-enix.com/ffxiv/...=1#post2692500
https://forum.square-enix.com/ffxiv/...92#post3969492
https://forum.square-enix.com/ffxiv/...33#post3116933
https://forum.square-enix.com/ffxiv/...87#post2861187
Confirmation that the team is looking into a suggestion/concern (note: most of these were implemented, from what I know of the game)
https://forum.square-enix.com/ffxiv/...=1#post1101676
https://forum.square-enix.com/ffxiv/...56#post3116856
https://forum.square-enix.com/ffxiv/...02#post3116802
https://forum.square-enix.com/ffxiv/...10#post3066610
https://forum.square-enix.com/ffxiv/...66#post3066466
https://forum.square-enix.com/ffxiv/...70#post3062370
https://forum.square-enix.com/ffxiv/...46#post3058146
https://forum.square-enix.com/ffxiv/...90#post2872190
https://forum.square-enix.com/ffxiv/...29#post2812529
https://forum.square-enix.com/ffxiv/...40#post2787940
https://forum.square-enix.com/ffxiv/...37#post2787937
https://forum.square-enix.com/ffxiv/...61#post2757261
Confirmation that a fix has been implemented for an issue and/or new feature reveals
https://forum.square-enix.com/ffxiv/...92#post3770692
https://forum.square-enix.com/ffxiv/...32#post3403632
https://forum.square-enix.com/ffxiv/...34#post2787934
Clarification on how a decision was reached
https://forum.square-enix.com/ffxiv/...75#post3684775
https://forum.square-enix.com/ffxiv/...11#post3655511
Asking to keep a thread on topic
https://forum.square-enix.com/ffxiv/...15#post3483815
Suggestion to log a bug report
https://forum.square-enix.com/ffxiv/...87#post2872187