Reason Why Kylo Ren was never really that strong

After watching the force awakens...for the 5th time, I have realised something...in episode 7, we see Kylo Ren trying to contact Darth Vader (his grandfather...OUUUU SPOILER") ofcourse, Vader could arguably one of the strongest Sith Lords, before he was brought back to the light side, bringing back his true self, Anakin Skywalker. Vader killed sidious...and as luke was trying to save him and bring him back home with him...Aanakin tells him that he has already been saved...meaning he has been brought out of the darkness. This is why Kylo never gains Vaders force wisdom, because if Anakin were to be recieving these force transmission, he would probabaly be thinking, "uhhh I am deffinitely not helping you, I want Luke to be saved and not harmed so I am going to watch over him"...