I think people are being unreasonably unfair to The last problem. The most common complaint I’ve read was that “it wasn’t the finale I had in mind”. And while it’s true (because the direction of the show wasn’t planned at all), that shouldn’t be a reason to say it’s a bad episode. It’s like saying that Smash Bros Brawl is a bad game because “it wasn’t a game designed to be competitive”, or The last Jedi was bad because “it wasn’t the movie I had in mind”.
Not to mention, the people sho usually complain about The last problem are the same people who didn’t complain the same way about other debatable episodes. There we some exceptions like Father knows beast or Non-compete Clause, but those episodes were hated because “everyone else hated it, so it’s ok to hate it, it’s socially accepted”. When it comes to the overall show, many people were benevolent until it was too late, which isn’t pretty good reasoning.
And you know that? I love The last problem. I think the story was very relatable. Most of us had friends and, after having a good time with them, we worried about what would happen in the future. How can I meet my friend again from a long distance? How can I see her grow because I care about her so much? Nowadays it’s not an issue because we have Discord, Facebook and Skype. And it was overall very well written, and this comes from someone who thinks Josh Haber is the worst writer in the show next to Michael Vogel. I think he did a good job asking the right questions with the right characters in the right moments.
I think the only problem I see in that episode is that I wish it was funnier. But other than that, I think it’s a very good episode. I wouldn’t mind watching it again.