Frentzen didn't play second fiddle to JV at Williams in 1997 and 1998 - he got slaughtered by the British media becaue he replaced Damon Hill and everyone at Williams hated him and NO Frentzen did not put in strong performances at Williams at all - he only one once when VJV wona championship - in that sense he did play seocnd fiddle I guess (I hate talking about those years of Frentzen's career). Then came 1999. Frentzen won two races and could have pushed Mika for the championship if it wasn't for an electrical failure 7 laps from the end of the European GP (ARRRRRGHHHHH!) Ultimately, it wasn't bad performances that got him back at Sauber, it was getting fired by Eddie Jordan, and both Prost and Arrows leaving. And by the way, when HHF drove for Prost and Arrows he did produce some excellent performances (e.g. qualifying 4th for the Belgian Gp in a Prost). Ultimately, his biggest mistake was going to race Formula Nippon in Japan rather than staying with the Mercedes F3 team. Heinz would have been WC's next to Mika but shit happens. And thats that. It all depends on the team. I say Fisichella is the most naturally talented because of his ability to push the car to its fullest and sadly the cars in recent memory he has driven have been shit. Fernando Alonso and Giancarlo Fisichella are not too dissimilar in their experience (i don't mean style - FA is much more erratic than Fisi). By this, i mean Alonso, at his time at Minardi was doing exceptionally well FOR THE CAR UNDERNEATH HIM. HE would consistenly qualify 16th or 17th, which isnt exactly "mixing it with the big boys". But for his racecraft - it was brilliant. Similarly, Fisichella did very well in that 110 degree angle "engined" Benetton, hammering Button and putting some nice races in the process (i.e Monaco and 3rd at Spa'). So, while Fisi's career definitely HAS been stagnating, his performance has only gotten better and the battle between him and Alonso next year will be awesome, provided Renault give them another good car. Thats just the facts, but personally, I believe that, in time, Fisichella has the capacity and experience to kick Alonso's ass.
P.S. Argonaut, please do not measure the natural ability of a driver by how much championships and points they have won. This is a huge misconception. Natural ability is seen in the driving style the respective drivers undertake and how consistent and quick their lap times are. If you ever go to a GP stand at a corner and check out how they enter the corners, you will see a tremendous difference. And remember, to win a championship, you need a mixture of a good car, team, natural speed and knowledge. I can assure you that Michael Schumacher is not the fastest driver out there, he is the smartest. Don't get me wrong, he is still bloody quick but not the quickest. For example, before he came to F1 he came third in f3000 championship to KArl Wendliger and Heinz-Harald Frentzen but when he came to F1 he excelled. Regardless though, now that Fisi has a good car and team around him - watch him fly!