Totally agree that it's something we should try to stop. I've been very skeptical about bots as well, but did briefly use @smartmarket to give a couple posts more money. But to your point, that doesn't add any real community value, it's literally just a transaction.

The reCAPTCHA notion is nice on taking actions that affect the rewards pool. Simple, not too hard for users, but if it thwarts most bots, great. Maybe there is a small window where once you do the reCAPTCHA as a human, there's 5 minutes of time that it won't ask you again. I'm moreso thinking about introducing friction onto Steem platforms if they are going to compete with Instagram and FB. On those, people Like stuff often, and I think we'd still want to encourage that from actual people. Not sure if a reCAPTCHA cool down makes sense though...

Side note, and apologies for pimping, but I just wrote yesterday about a bot idea for DTube where the bots upvote based on views, nothing else. So creators have a floor of earnings so long as they get X amount of views. Long post + video here: https://busy.org/utopian-io/@gyrosean/how-dtube-could-use-voting-bots-to-refocus-emphasis-on-views-and-scale-creator-monetization