Its imposible to be the best in your position and not be WC. The fact that you can get into any team in the world (since you're the best) defines the term world class.
Most people wouldn't define Cashley as world class though, too many of them let their hate blind them, common practice as football fans really.
Cashley is up there but I actually think world LB's are pretty poor currently. He's very solid defensively and he'll support the attack, but if you watch him with the ball at his feet he's really clueless at times. He'll panic and just play it backwards quite often. He's much more tentative compared with his Arsenal days.
Evra is very comfortable going forward and always looks comfortable when he has the ball. He is a bit dodgy defensively though, I think you're overrating him in that department Meta. The CL semi in 2008 Messi gave him plenty of problems and was easily our best player in both games, whereas CR did very little past hitting the bar. I'd personally take Evra over Cole as he's a better all round footballer, but neither are great compared with previous generations.
messi was our best player?
yaya was our best player as he cut off SOOOOOOOOO many man utd counterattacks. xavi was second best. both enabled us to dominate the tie. everyone else was a way below them. messi only had 2/3 dribbles and shots on goal over the course of both legs, only created a few chances for others (couple for eto'o in camp nou, one for deco at OT) and stood there doing nothing as scholes scored the winner. he wasn't fully fit, sure, but he was never our star performer. he tried several times to beat evra with a dribble and only really managed it with that one legendary flick.
and what previous generations? roberto carlos? you are aware he couldn't defend for shit, right? I mean, that's an exaggeration; as he could make good cover runs and tackle, but he was caught out of position so often. certainly worse than evra in defence. and about as effective in attack (although more spectacular).
maldini, I'll grant you, was a class apart. but maldini is an all-time great. he'd stand out in any team in any era except il grande inter as they had the original maldini (facchetti).