My take on it is that he's not able to play to his strengths with the way the team plays at the moment. Lennon is an intelligent player with great movement and he's good at spotting options. However, he has to receive the pass to be able to do something. Many a time his runs are being completely overlooked with our team getting collective tunnel vision. The way I see it, he is often used as an outlet when (insert player name) has run out of options than used as the weapon he is. Quite a few of us drooled at the possibility of having two great wingers when Bale was moved forward, but it never caught on. Not because you can't play with two wingers, but because our team then and now seems utterly unable to comprehend that you can use BOTH sides. When teams started to double and triple up on Bale, we still kept bombing the ball in that direction hoping he could perform magic instead of switching sides now and then.
In my opinion, Lennon is the winger equivalent to Darren Bent, he has to get the proper service. If he does, he will deliver more often than not. When Lennon broke through, the game started revolved around serving him, as we hadn't had a player with such speed with the ball since Ginola. With numerous injuries the team gets used to play without you, and getting up to grips is not only about getting fit yourself, but having the entire team play another way since you are not replaced by a player with your own skillset. And Walker doesn't provide as well as Corluka or even Hutton did, he is quite often found ahead of Lennon leaving him with defensive duties, hence "Lennon being good at tracking back". I think Lennon's percieved decline has more to do with playing in front of Walker (and Johnson) than being found out or having gone backwards. It's about reading the game knowing when to go forward and when to hold position. Walker to me isn't quite there yet. Corluka was Lennons soulmate as such, but he had a few other weaknesses that couldn't fully compensate for that particular ability.
As whole, we are kinda undiciplined on the flanks. I think I can see some similarities the way BAE now are getting caught out more often when Bale has gotten a more free role, with the way YPL got slated when Davids, Malbranque et al decided it was more fun playing inside than keeping shape. It's not easy when you're still being expected to go forward covering an entire flank alone. This is probably easier to confirm/debunk for those of you at the stands, but it looks that way to me on TV at least.
