LONDON, England - Formula1 legend Jackie Stewart believes F1 could do with a new World champion after four years of domination by Red Bull's Sebastian Vettel.Speaking at a lunch to preview this month's Motorsport Hall of Fame event, Stewart, a triple title holder, said: "I think it would be better, I think it would liven things up... It would be refreshing. Four times is a bit greedy."Vettel, 26, became the youngest quadruple champion in 2013 and won the final nine races of the year. Nobody has beaten him since July, 2013 Red Bull has also won the last four Constructors' titles and will start the 2014 season in March as favourites.Fellow German Michael Schumacher, who retired in 2012 at the age of 43 and is currently in a coma after a skiing incident in France in December 2013, won five titles in a row with Ferrari from 2000 to 2004.Stewart said: "Nobody is up there for ever. The world moves on and I'm sure that will be the case. I don't know if it will be next season. Red Bull is pretty impressive and now has more money coming in from sponsors than from Red Bull because they are getting TV coverage."'NEW ENGINES'2014 will sees a new V6 turbocharged engine replace the V8s - fuel economy, driving styles and reliability will be a bigger concern.Red Bull boss Christian Horner warned on Wednesday 15 2014 that the opening race in Australia could see a significant number of retirements, perhaps half the field. It should also be harder for Vettel to run away with the championship thanks to a controversial decision to award double points to the winners of the final race in Abu Dhabi.Stewart expects 2013's runner-up and past double champion Fernando Alonso to get the better of team mate Kimi Raikkonen, the 2007 World champion, at Ferrari - they will be team mates for the first time.Lewis Hamilton, the 2008 champion with McLaren and a winner for Mercedes in 2013, is another favourite even if questions had still to be answered about his consistency over the course of a year. Stewart said: "I think Lewis is the fastest driver in the business, just sheer speed. When he puts a quick one in, he's the master at it."The Scot said he was sure McLaren's Jenson Button, the 2009 champion, would not let the death of his father John on Sunday 12 2014 - a constant presence at races and a hugely popular paddock figure - affect his racing.Stewart said: "A racing driver is a peculiar animal. Look at all the deaths we had and yet for whatever reason we still raced... I think racing drivers probably are tougher than most people. John lived the fullest of lives but had a heart attack at 70. There wasn't much life that he'd missed."