What excitement did Ricciardo ever bring to a GP weekend before getting his Red Bull seat? (admitedly Dan looked slightly better in the Toro Rosso than Vergne, but still doesn't invalidate my point)
The point is (with all this second tier and first tier drivers) the difference between the very best (Vettel, Hamilton, Alonso) and someone like Jean-Eric Vergne is very, very small. It is not that Ricciardo at Toro Rosso blew our minds out, he was JUST a little better than Vergne in most area's. We can only look at the races and at the results, very general impressions. Red Bull knows everything about the drivers, from apex to exit-speed, reaction-times, bloodpressure, ****-and pisslevel during the day (joke, joke!), tyre and bodytemps (half joke), andsoforth. Sensible F1 teams make decisions based on details to the 9th degree.
Really, we must forget the idea that the drivers that Red Bull are looking for are going to blow their respective teammates away. People like Vergne, Buemi, Alguesari are too good to be blown away.