[CaptainCrunch]

I think that Wise and old is great, we don't know how powerful he is in the grand scheme of things, and realistically how trained he is, he really had no one to guide him.

The argument is that while Luke was powerful by the time he hit Return of the Jedi, compared to the Jedi of the OT he was not really trained all that well, and that's why he was so heavily tempted to fall to the dark side in ROTJ.

And maybe he's vulnerable now . . . seeing all of your jedi students murdered, having a possibly incredibly powerful threat show up.

That would first of all scare the crap out of him, his anger at himself over the loss of his academy

Fear leads to anger, anger leads to hate (he might hate Snoke for turning his nephew), hate leads to suffering.