you should only ever accept advice from people who have succeeded at the exact thing you're getting advice on.

Anything is OK between 3 x 8 to 5 x 10 so basically people can grab whatever dumbbell happens to be free and as long as they can feel they exhausted the muscle and really could not do much more it is going to be okay.

What's your big 3 total? ;)

Progress tracking is for athletes, professionals, yet another thing the average guy does not need. Just a good pump / exhaustion of the targeted muscles that makes one feel vigorous and thus motivates one to come back next time for more.

Progress tracking is absolutely for the average guy. The problem with your idea is that said person is likely to see no progress (either in terms of quantifiable strength or more qualitative "looking good") since they're not actually building any muscle.

Then they'll really get discouraged.

Anyone interested in looking or feeling better should try a real weightlifting program. Not only because becoming strong is fucking fun but the mental benefits like discipline, dedication, and pushing your limits are just as good.