My view is that we should be willing to go a bit above but not way above what the current highest earner is on.
The players should understand the reality that we'd have to pay bigger wages to get good players to the club - players who can help the current players achieve their aims. It's a choice between that or more of the same.
Then you have to ask the question about whether the players deserve such loyalty from the manager in ensuring wage parity, when in reality they'd all be off in a shot as soon as a better offer came along.
Increasing the wage ceiling is also a long term inevitability so if new signings were seen to be on more money, the current players should know that there's scope for their own contracts to improve in the future, as long as they perform.
Finally, wage parity is assumed to be key in maintaining team spirit. Well, I'm not sure I see too much of that right now.