There's a lot of logical inconsistencies in Jon's storyline that really degrades the impact of his final act.
- As you mention, where is Ghost ever since Jon got lost?
- Why would Qhorin sacrifice himself for Jon in the show? Earlier in the season, he explicitly told Jon that he should not so willingly lay his life for the watch cause no songs will be sung of him. Yet here Qhorin does exactly that. In the books, it's better understood because Jon has earned Qhorin's respect by that point, but on the show, Jon is portrayed as even more incompetent and weak-willed, especially getting lost with Ygritte and eventually captured. Moreover, in the books, it's Rattleshirt who orders Jon to kill Qhorin to prove his worth, and Jon is much more reluctant to do so until Qhorin urges him on ("Remember your orders," "Is your sword sharp, Jon Snow?")