I went through their site and e-mailed a question about vampire attacks.
I didn't expect them to change anything just because I e-mailed them. But they didn't even send one of those generic "Thanks for contacting us! We are always excited to hear from our fans, and are committed to making a better product!" responses.
It seems like they pick up some of the general sentiment from the community, considering some of the changes they made to Skyrim from Oblivion. So who knows. I think it's worth bringing things up.
This. You'll never be able to be all "hey brothesda what're ya up to today?" with them, since that sort of fan/developer relationship can make things pretty hairy sometimes. But Bethesda generally responds to fan input/outcry, in the sense that they address mistakes and occasionally take inspiration from PC mods.
Now, that's not to say Bethesda's perfect, or that their games get progressively better. "Addressing" mistakes means making a change to whatever's supposedly "flawed", and that change can end up being even worse to some people. But in the very least, they don't make the same mistake twice; or at least not in the same way.
edit: Got carried away there. To answer your question, the official forums on the Bethsoft website are probably your best bet, especially if you want to discuss future features/ideas. No doubt Beth reads those. If you really need to directly contact them about something, you could probably call their office, like other people have said. Hopefully you won't be wasting their time.