Hayden was specifically directed by George to be petulant and whiney and he would beg George to let him try to be more mature, but George wouldn't let him do it until Episode III. I can't find the quote right now but I've posted it here before - there was an interview where Lucas directly stated this to be the case. Hayden signed on wanting to play young Darth Vader, like anyone else would, but Lucas told him "No, you have to be a whiney teenager first, then you'll get to play Darth Vader."
That said, I feel like Anakin's ghost has to show up at some point. It doesn't make sense if he doesn't. It already kind of doesn't make sense. Kylo Ren should be able to just go talk to Anakin's ghost. They'll have to come up with some sort of reason why he became obsessed with Darth Vader when he could literally just go talk to Anakin Skywalker for the pre-TFA time period, unless either a.) he for some reason was not able to talk to Anakin or b.) idolizes Vader and hates Anakin and treats them as separate entities.
The latter wouldn't surprise me. The TFA novelization seems to imply something like that actually, because Snoke and Kylo have a dialogue about the causes of the fall of the Empire and Kylo explicitly knows that Vader turned on Palpatine. Snoke says something to the effect of "It wasn't strategy or tactics that brought down the Empire - you know what the truth is" and Kylo responds "Sentiment." Snoke then proceeds to talk about how Vader lived an exemplary life that was marred at the end by an unfortunate emotional turn to weakness, and that Kylo will have to overcome things like this for the good of the First Order. This is foreshadowing for Han, obviously. But anyway, if Kylo thinks of Vader and Anakin as separate beings, like how he told Han that he "destroyed" Ben Solo, then he might not want to talk to Ghost Hayden.