Walcott can run fast, but can't cross and has poor decision making. He'll score more often than not when he is clean through but that's because he doens't in those situations have to decide whether to pass shoot or cross. Personally I don't think he is such a loss, but strories of his departure (if true) are worrying only if there is no one to replace him.
Also, let's recognise that there isn't much going on in football for the press to write about and so they are scratching around for stories and will make a mountain out of a mole hill. Ask any Arsenal player if they'd like to see signings being made and they'll say "Yes"; ask them what would they think if X, Y, Z left and they will say "That would be worrying". Put these two together and you can come up with a whole load of "Emirates Departure Lounge" type stories.
For all his faults and stubborness, I do believe Wenger to be an intelligent man who knows what he is doing; what we don't know is what handcuffs he has restricting his options.
WIth all this toing and froing I think we can discount a serious challenge for the title, but I think most fans would be happy to see signs of improvement over the last couple of years, and a recogniition of the need to eveolve the team beyond the tippy tappy stuff.
Of the players who are leaving, CLichy is no big loss as I think he is a weak defender who is prone to the regular blunder. Nasri, when he is good he is very good, but he tends to be good when the team is playing well and on top, and is not someone who will regularly drive the team to victory is tough games. He dithers too much in my opinion, and lacks a directness that is needed to pressurise defences. Walcott's goes missing too often in games, and the groans of the crowd when another of his crosses are over hit are go out says it all. Even Fabragas has had a lucklustre season and has had a sullen look about him - his heart is elsewhere, and in the last two seasons during times when has been out with injury the results haven't been that bad.
So, even if these guys leave, so long decent enough players come in I wouldn't be too downhearted. I can see th eteam becoming a more competive unit without these players. If I had a choice of who to keep, I'd like for the Spaniard to stay, and I'm really not bothered about the others.