I'd say the Heat experiment has been a success to date. They're two home wins away from a title, which by almost any measure is a success for a team that finished 5th in the East last year.
The Heat are definitely thin, but this isn't a one year experiment. If we get an immediate hard cap, the Heat may have some issues adding to their team (depending upon how low the cap is), but if the rules stay similar, they'll be able to add to their team again next year with the MLE and bi-annual exception.
If the Heat fall short, I'll be glad; it's always nice to see Goliath lose. However, I wouldn't draw many conclusions about Riley's plan yet, or the future of the Heat; I'm sure they're going to be fine.