It may be useful to separate out the issue of a choice of symbol from the issue of its status (official approval or individual usage). On the choice of symbol, if we endorse the apparent bias towards articulation as a defining criterion in the IPA then criteria like diachrony, perceptual similarity and even phonology are secondary at best. (Note that in making this inference from current practice, I do not wish to pre-empt any debate about whether the articulatory bias is valid!)