I agree with you mate. Kone and McGeady are woeful and we never should have purchased them. It is more wishful thinking than a realistic expectation that someone would come in and offer money for them, because they are both truly pony. With Barry and Pienaar however, and indeed Gibson, there is genuine talent there. Pienaar could still do a job in a less physical, or slower-paced, league. I think the same is true of Barry.
However, the fact is that Barry aside, the five named players don't play much and therefore I feel we could risk losing a couple of them without immediately replacing them. Or we could replace them with youngsters who we send out on loan to develop, or loanees to warm the bench. The key word is risk, I suppose. On the one hand we risk wasting wages by keeping players around who, quite frankly, we hope will never have to actually play for us, but if we sell them and only receive minimal transfer fees then we risk not being able to keep the squad at a certain size.
This problem of deadwood is partially related to us not being very sensible with how we dispose of players. We tend to hold on to them for too long and by the time we are actively looking to shift a player, they are at a stage of their career where no-one else wants to pay money for them. We would do better to look at how the New England Patriots continually rejuvenate their roster by moving players on when they have reached their peak and probably have a good couple of years left in them - sure, you lose a year or two of great performances from that player, but you create space (in terms of the numerical size of the squad and available funds for wages) to bring in new, upcoming, younger players. We have obviously held on to Pienaar for too long, from this point of view.