1. True, Touchwiz was atrocious the updated Samsung One UI is worth trying out and is one of the best UI's I have ever used and I actually hope to see some of the benefits of the new UI in Stock Google one day.
2. Samsung has gotten better about updates and updates do not always mean better experience for the end user, ie "Honeycomb".
3. The S10 is worlds apart from the S8 in design and build, I would not knock it til you try it. There are a group of users that want the latest and greatest and I too used to be one of those. Its worth the wait sometime to ensure4 everything works and you are not all of a sudden finding out Google Pay does not work or Android Auto. Oh and some of the slow update for your s* is because of Verizon not Samsung
The best of the best IMO
Google Pixel for updates and Software
Google Camera software and Post Imaging Hardware
IOS IMessage
Samsung PAY
Samsung Hardware and build