Is it too hard to put the signature line over to the left?
From a technical stand point it's not hard at all.
But I'm not sure if placing signatures on the left side would be good for usability.
The whole point of moving them to the right is to get them out of your sight and make it easier to follow threads by scanning the posts downward.
After all, how many times can you read the same set of signatures over and over before it gets annoying?
When you encounter a new user (or a new signature), you'll probably notice it and read it. But when constantly conversing with the same set of people, you would probably just skip over their signatures, since you've read them many times before.
If the signatures are on the right-hand side, it makes it easier to skip over them to the next post in the thread.
That's why placing the signatures on the right side seems like a good idea to me.
Maybe I'm mistaking.