his W is his best skill before lvl 6, also get oov and run at anything while being immortal. hes fine, you just gotta abuse his immortal status i guess newbies wont.
well, we can say the same about lich offlane then, hes really nothing special apart from a mek (if u go for it) and deny a bit of carry farm but he'll get free jungle and kill ur t1 easily if they go for it.
I'd take doom offlane for ez mmr anyday, or clock/tusk/dank seer. core lich is underwhelming
edit: tho hes really good for dual lanes off, or any dual lane. as long he leaves the farm for a useful hero