Maldini is quite possibly the best left back ever - that's like saying unless you're as good as, for example Baresi, you're not a world class centre half. I think Baines in his prime would have slotted into any team in the world, so I'd say he was world class.
World Class for Everton? As fairly recent players (in their prime playing forn us or not), I'd go Southall, Gascoigne, Lineker, Kanchelskis, Baines, Etoo, Rooney, (Lukaku I'm still unsure about).
As far as being able to play in any team, Gravesen left us to join arguably the best team in the world (toss up between Madrid and Barca) although I wouldn't call him world class - what does denote a world class player?.