I have some "off the wall" suggestions for wasted talent in F1,
Tacuma Sato, never really got the right drive, showed signs of greatness in an unreliable off pace car, Suzuka 2004 where he was mixing it up with Ferrari's comes to mind, then 2005 happened which was a bad season for everyone in F1, the tire rule was stupid and more or less ruined a season of racing, moved to Super Aguri in 2006, which was a former Arrows chassis evolved by Minardi into the 2006 race car, was scarily off pace immediately but the last 3-4 races he dragged it up the order a lot to finish 11th? I think at the last race of the season, 2007 was a great year for Tacu in such an underfunded team with what seemed to have no development whatsoever,
Juan Montoya, came into F1 in a fire ball of excitement, the very fast and equally unreliable Williams in 2001 really showed his potential, left Williams with a win at Interlagos in 2004 with a car that really couldn't keep up with Ferrari at all, then McLaren and 2005 happened, 2006 started, announced at the USGP that he was leaving F1 for NASCAR at the end of the season, mainly because it was pretty clear to everyone that he was going to be replaced by Lewis Hamilton, didn't tell Ron Dennis before telling the media he was leaving and never raced F1 again as punishment, and didn't race again until his contract expired with McLaren, his last race in 2006 was the Ford 400 at Miami which ended in a fire ball,
Michael Andretti, a case of 'wrong place, wrong time' leading up to the 2016 Indy 500 Marco had a rant about how his father Michael never had the same equipment as his team mate Ayrton Senna, knowing McLaren's history its entirely possible to be true, had this been a year later Michael' F1 story could have been very different,
Robert Kubica, I was a massive fan of him by the 10th lap of the 2006 GP of Hungary, a race that is so weird that has to be seen in full to truly be believed, its a fantastic race, I still believe had he just taken a breathe or two and calmed down a touch he would have won on debut, he was sideways or backwards so often yet he was do fast in the changing conditions, so fast that he got Villeneuve sacked more or less, 2007 and 2008 were fantastic seasons for him, but BMW let him down by shooting themselves in the foot and 'ending development early to start on next years car' I also still think had BMW kept up the development he would have been world champion of 2008, a move to Renault later in a sub par car with an inexperienced team mate didn't yield results they were after, the unfortunate wreck in rallying changed the path of his story,
Bruno Senna, I'm sure everyone will rag on me for this, because he finished 17th while his team mate Maldonado has Williams only race win in the last 10 years, but leading up to that season he was on the up, his half season in Lotus proved his capability constantly matching his team mate Vitaly Petrov who had been in the team for a while and knew the car and personnel better, lets ignore his stint at HRT....
Allan McNish, one lack lustre season in a brand new team, with a whole new car, getting beaten by a Minardi on debut would be the norm for any debut team usually, but getting beaten for 5th by a Minardi on debut isn't usually believed, a great start to a season that seemed to be abandoned as a testing season from round 2 onwards for Toyota, unfortunately both him and Mika Salo were both dropped for new drivers in 2003,
Last one, Ryan Briscoe, explosive test driver for Toyota in 2003 was usually as quick if not quicker then Da Matta and Panis at test days and T-car Fridays when allowed during the year, won the F3 Euro series in 2003 as well, expected to see him in Toyota full time in 2004 but was ignored while F3 runner up Christian Klein got a seat at Jaguar, eventually ended moving to Team Penske in Indycar for 5 years, neither Penske nor Briscoe really seen the best out of each other within Indycar, had Moderate success in the ALMS in the Penske Porsche LMP2 car, now with the Ford GT Ganassi program and being a solid pair of hands,