Whilst I have to admit 'I got lost' with all the technical side of it, I do love this idea!
Having come from Facebook I do miss the emoticons, and I feel the 'worthwhile' one is a particularly a great idea. I do agree that I too have read posts that are putting across a good message, but I may not agree with all of the content, so might not want to upvote it, but would click a worthwhile emoticon.
Also, I feel sometimes that writing a comment might come across as being controversial or attacking the author in some way and it could be difficult to write and share 'I thought your post was putting across good information but I disagree with some points'. Some people may be happy to discuss the points of disagreement and others may not, or as you say there may be a lack of time to go into this in detail, but the post does deserve some recognition.
It would also be good for the emoticons to be used in ranking, which could help new people and posts more where there aren't many up votes or comments, and this would encourage some response!
I'm not sure I like the idea of putting an end to rewards after payout! So far my posts have done really badly and I am hoping that they may be seen more in the future. Surely it is the most valued posts that will keep receiving votes after the initial payment so they most deserve those extra votes and rewards?
Thanks for your post, you get a 'worthwhile', 'upvote' and 'approval' from me! Ooh maybe that brings up another issue of how many actions you can do on one post!!
I'm going to vote for you as witness too as this is important work to help Steemit work as it's intended long term. :)