These schemes reduce orphaning and allow miners to make a greater profit. It's not hypothetical, Matt's fast block relay protocol is the simplest and least effective of this class of scheme and it is used almost universally today to carry blocks between pools. (A good thing too: otherwise there likely would only be a single mining pool now...).
In the last week or ten days, Matt posted that he was looking for someone to (paraphrasing here) "take over the running of the relay network server".
If the relay network server goes unmaintained, what will be the consequences? Is this server a point of centralization?