There needs to be standards in place, time limitations etc.Absolutely. You can't have transparency and no way for people to raise their salary.
Transparency is great, but often times one person makes more money than another because of a combination of skill set, negotiating power, gender and relationship status, not to mention relationships with other people in the company and the word we hate (favoritism).
There's a way to sidestep all those. First of all, negotiating power does not enter into the equation at all, since the pay is all public. It's (rightly) illegal to discriminate on gender (and I'll go headbutt a wall quite hard if the thought "we can pay her less because she's a woman" ever dares to enter my head). Skill set is measured by the results you bring to the company, not by some vague abstract measure. As for nepotism or favouritism, that just takes some minimal self-discipline, imho...
So while I am 100% on board with transparency, I also believe it can have a backlash. There's no way to predict it, but creating path for someone to increase their salary and letting it be known before they sign the contract is a good idea.
Too many people, entrepreneurs and others, seem to be afraid of paying more money to employees... I find this whole fear ridiculous. I want to have a good reason to pay someone more, because that means they're bringing a multiple of that extra value to the company. If I pay someone £16k a year, it means they're bringing relatively little value to the company. If I pay someone £50k a year, that means they're bringing several times that value to the company.
In short, being afraid of offering ways for people to earn more seems silly to me.