A Model Release form has no legal status as such, and generally you don't technically need one. It just saves a lot of trouble and misunderstanding of what the legal Rights position is.
It simply outlines the basic legal status quo, and reiterates the fact that the subject/model has no rights to the pictures, and that they are likely to be published. It just re-states the legal Rights position, and does not change it.
It can be written on the back of an envelope, and so long as the model is clearly idenified, and the pictures (where/when), and you as the photographer, then that is all it needs to do to avoid any future misunderstanding. And that is all it can do - avoid future misunderstandings or claims to Rights. This is what publishers want for a hassle free life.
Stuff like a 'consideration' is often added to emphasie the point (a fee, set of prints, whatever) and some forms set out in endless detail - and pseudo-legal jargon - all the places where/how the images may be freely used. This is not necessary, but some see it as adding either additional weight or clarity. It can also frighten some subjects off, so some people leave it out unless it's particularly pertinent.
None of which actually deprives the model of their legal rights either, and it is still very possible to get into trouble if the images are used in a way that
misrepresents the model. That is the key word here - truth. And that is how the paps get away with it. A picture of Jordan falling out of a nightclub and clearly drunk, is okay as it was taken in a public place and she was, in fact, drunk.
But if that same image is used by, say, a massage parlour implying that she's a hooker, then you're in deep 5h!t. Or in an ad where she appears, falsly, to endorse a product. Truth is a very strong defence and courts will recognise that. But by the same token, juries take a very dim view of misrepresentation, and unfair exploitation. They don't like lies, which is kind of understandable
That seems entirely right to me and if you behave properly you should never get into trouble. However, that doesn't stop people/models kicking up a fuss when they see something they don't like and in those instances a signed Model Release of some kind is obviously helpful. It doesn't change the law, but simply states that the model was aware of their rights when the pictures were taken.
Most legal issues never get to court, but you can waste a huge amount of time and solictors bills simply establishing that there is no case to answer. This is the value of a Model Release form.
Edit: There is no legal distinction between editorial and commercial. However, if you have abused a Model's Rights and made money out of it, then the case to answer has a bit more meat to it. Since this is probably the most common area where photographers get grief (ie "you took my photo for free and now you're making money out of me") most prudent agencies and publishers will want some kind of reassurance against this.