For a word in the other direction on energy missile.
So long as you cannot target attended items (apparently the person who wrote the power thought that the base rule was different than it actually is, they thought that if you targetted a person then you could not target any of their equipment also) there really isnt any problem with it.
It is a specialty power (kineticist only) the targets have to be very close to one another (each has to be within 15' of all other targets, so basically two squares, even early on creatures will spread out to get away from area of effects and the like and later on they do the same plus creatures tend to be larger or have other problems), it is always second level so things like spell turning really fry it, and it is always elemental damage (although it can be shifted through 4 different types).
The save dc is not even out of line when you compare it with things like energy ray. Most of the time, even at later levels, using energy ray is a better bet. It simply denies a saving throw.
Having a specialist power which winds up having a higher save dc at much higher levels (when direct damage is at its weakest) just hasnt been a problem in actual play, especially when compared with the other options out there. A high dc would matter for a save or die, but on direct damage? eh.
Overall the psionics system has a whole lot fewer problems than the other magic type of systems. If it is any sort of indicator there really isnt much for extreme builds on optimization boards whereas there are tons for other types of magic.
The main issues are shared between the two. Shapechange/polymorph like effects have some issues with the assumptions of the game and things like that.
Still though, each type of magic has things that they are both good and bad at. Focusing just on the good and ignoring the bad is not a good way to go. Psions tend to be the best at direct damage, divine rules in healing and status mitigation, arcane has some majorly incredible illusions and the like.