wel HE needed to be killed because he didn't want to continue so letting him be killed by his own son is a suprise (which as we know could realy help star wars plots ) but the character just isn't the right one yett . but kylo can always go threw extreme changes bcuz he's so confused and insecure about him self . if the director pulls it of to make him into  someone with interesting emotions that drive him insane or just make him sympathatic by making him regreting his diccisions and maybe sacraficing himself  to defeat supreme leader snoke ( a.k.a. mashed potato face . )that will be awesome and could give the character some depth . so as bad as it may look he can always grow to be a amazing character.
let's hope the next director doesn't fuck up.