Developing with a secure mindset means that all user-supplied data is considered potentially malicious, so it shouldn't really be a problem at the end of the day but using the relevant $_GET or $_POST superglobal vice $_REQUEST does make for better and more readable code.

Should developers continue to have access to risky functions, even when there are safer alternatives present in the core language? Some would argue that by not having the temptation in the first place, that the resultant software developed will be more secure by default, and that if developers really need access to a similar capability, they can code it themselves. Alternatively it could be argued that developers should be aware of their language of choice's limitations before attempting to code in it. Site after poorly coded site, project after poorly developed project, and sites such as the show that this is an extremely optimistic view to take, and one that is not borne out by reality.

In the future it is possible that $_REQUEST will go away completely, and developers should begin looking through their code to see what they can start doing now to make their code ready for future PHP versions, with the side benefit of making it more secure.