I also wouldn't mind seeing a TIP button that makes it really easy for someone to click TIP and choose to send steem or steem dollars to someone as we read their post regardless of how old the post is.

I've brought this up before. I think that would be a fine addition to posts. It makes sense for long-term earnings. If you like something from six months ago, send them a few STEEM. It's probably more than your vote would have given them at the time anyway.