I like the fact that you are considering modifying sig limits, and that you are asking for user input, but I don't like your idea.
A) The main problem of these sigs are height. The length doesn't matter, it's the height that becomes the regular problem.
However, I think that if somehow you did lengthen the sigs to fit a whole post - it would look really slick. I'm not sure if I want to sacrifice the height for more length though.
I don’t think the resizing idea is disastrous, and it wouldn’t be a large loss - but when it means we have to lose animation, I’m less forgiving.
B) Animated sigs are a huge part of this forum. You cannot get rid of them.
Newgrounds is about Flash animation, is it not? How silly would it be for someone to come onto a site about animation, and find out that you can’t even have animated sigs.
The truly annoying sigs are stroby ones - and they aren’t allowed anyway.
Don’t get rid of animation, it’s great!
Your third party is stupid. I never found a problem with the sigs on this site, it does not make 'Newgrounds look shitty' or seem like it has ads. I don't think it was ever a problem.
I’m all for change, since I think that sigs are actually a big part of this BBS, but I think that your suggestions are too drastic. No from me.
By all means change the sigs, but don’t sacrifice this much for it.