First i don't claim anything else than being a guy who drove Yamaha since the 125 RDX, both on road and tracks and knows a little about them, enough to comprehend what Burgess and Roberts say without ambiguity or risks of false interpretation.
Then i am not talking out of the void, just a look at statistics will show you one or two things: Rossi won 4 titles for Yamaha in 7 years, Lorenzo two since 2008 that's his sixth year at Yamaha, then Stoner is gone since Rossi's titles.
There is no doubt that Rossi (and Burgess) who had a strong influence in the development of the 2013 M1 also had 500 cc experience, but Lorenzo technical input have been different from the end of 2010, just as it have been when Max Biaggi was riding the 500cc Yamaha from 1999 to 2001 and never won a title.
For the story he also was in the class of Cadalora, Kosinski and now Lorenzo when it comes to style, and never really came to grip with the back-wheel stearing style, Yamaha did provide him with a chassis to match his style in 2000/2001, but he didn't win the crown did he? Rossi did on the NSR500.
There's no point arguing vs guys like Doohan or Roberts, what they know about bikes applies today the same way and if they say Marquez makes the difference because he can slide the bike when he needs it, it's pretty obvious to me why. It's been this way since 1978 and even the partial at every tracks show why.
The real question is why some people still can't figure it out and got to extreme length to justify opinions which are neither based on technical nor historical points, apart for pretending that K.R and Burgess doesn't know what they talk about or too old to compare, as if themselves knew what changed in the bike design and chassis geometry...
Something else: When Roberts was Yamaha team manager, he managed 6 titles with Eddie Lawson and Wayne Rainey, Spencer was also a BIG slider and won a title for Honda vs Roberts and then Lawson.
Stranglely enough it's not related to the similarity you mention, because from the time Rainey was out and Robert left, Doohan won the title five times in a row, then who won the titles in 500 for Honda and who won a single 500 title for Yamaha?
So you suffer from lack of clear memory recollection or still playing this funny game, the fact remain, the guys who won multiple titles in 500 were all mastering the slide, and to be more precise, i don't think Lorenzo would have done better on a 500 than Kosinski, Cadalora or Biaggi, especiqally vs Lawson, Rainey, Doohan and Rossi...
It's not the name and the emotional B-S it's the style and the capability to over-ride the bikes.