Realistically he hit 3rd because other teams were inconsistent. Merc didn't have the best car, but it was more consistently average whereas AM were good then bad, McLaren were bad then good, Ferrari were...Ferrari.Expect better than 3rd in the championship in almost certainly not the clear 2nd fastest car?
Also beating his teammate by 5 places in the standings?
Lewis had a very good season last year. I really don't know why people like yourself are writing him off.
I'm not expecting anything from him this year. The car is at best the 4th fastest car on the grid now, maybe even battling for 5th fastest with the Aston. He knows his time with Merc is up and he knows at best he might be looking at 5th or 6th in the standings.
I think Russell is a good comparison where he's probably as fast as Lewis all things equal, but makes stupid mistakes. Charles is also quick but has binned it once or twice, possibly down to him outdriving the car given how Carlos was slightly slower but didn't make said mistakes.
So in summary, I agree that his experience makes a difference - consistency is king, but given a well rounded and competitive car, Charles and Carlos would be just as capable and more interesting in terms of a title winner.