So far the only relevant surveys they did since launch was about nerfing mid-league and about availability of endgame content for legacy.
As I said, the devs are usually very aware of the community feedback, especially on the big issues. Not just in the forums, but also on reddit and their discord.
That doesn’t mean they always follow it, though. They have their vision for the game and stick to it. But they do change their minds on things due to community feedback, like the recent adding of LP to the loot filter, which was always something they used to be adamant on not adding.