I, personally, welcome all friend requests. And am also guilty of just sending a FR without an accompanying tag/comment... although if I happen to notice that someone prefers to also get a comment/tag/message before a FR I'll do it.
Everyone deserves to be commented on before someone sends a friend. But, I am also guilty of it even though I do try to comment before. Keep up the good work in your new direction. I think it is a great choice on your part.
My dear the truth by one perception is that they may not feel strongly about your work, but the way you look may be appealing so though they have nothing to say, they wouldn't mind meeting you in person instead. .02
I get drive by friend requests. But never answer them. If they aren't willing to take 1 minute to send a comment or tag, or better yet a message explaining why the want to be friends (one line will do) then the odds of any real networking are remote. I can't in fact recall a single such ignored friend request where I ever heard from them again. Shows they weren't interested in networking but still couldn't shake their old MySpace habits.
Tags are great. IF it's either "I want to shoot with you (or, better yet, pay you)" or "Thanks for a great shoot, love the images." Tags like "Thanks for the listing" I don't mind, but I can do without.