After talking more with the guy whom I've been building a new character for, I've come to understand that some of the information I posted in my first question was... inaccurate. What he wants is a "sneaky" character that does not cast magic (as in lightning bolts, fireballs and so on), but does not necessarily mind actual arcane type characters (or psionic for that matter). He would rather be a ranged user and his definition of "sneaky" is less regarding stealth but more towards his character's personality, which ultimately needs to be reflected on the build as well.
What he is looking for is basically something that allows him to (but not necessarily limited to) dominate/charm, telepathy, invisibility/phasing (not the same thing but has the same approach character-wise), fear effects and so on. Upon first look, all of the signs pointed towards psion which has the majority of those aspects (or all of them when applying the right items/enchantments to it).
But there is a catch, team-wise, putting him as a psion is a bad idea. We are a team of 4 players where the team is currently formed out of the following: Psion (main controller), Cleric/Warlord hybrid (yours truly, main leader), Ranger (the guy's current character and the main striker) and a Swordmage (main defender but generally built specifically for a striker role for some reason). Now, eliminating the only true striker out of the team and replacing it with a controller is considered a poor choice, and even if we had the whole team reformed the person who plays the swordmage now wants to be a Druid controller next, which puts me in a difficult position regarding telling the guy whom I'm building the build for to go for psion.
So, is there any chance there is a class that can function as either a defender or a striker (if it's ranged, then only a striker I suppose) that does not use elemental powers, has some sort of affinity with the list of things the guy is interested in (charm, phasing, illusion, invisibility, telepathy, bluff and domination)...
Personally to me it feels that the only route for him will be either a psion or a wizard, both of which are controllers and I'm extremely shaky about a wizard considering how much dislike he has towards any sort of mage type character.
I remember that a warlock might be a good option in such a case but I might be mistaken, I'll need your advise on this one (since in the following several sessions there is a good chance that his character is going to die and he will need a replacement).