Oushitsu Kyoushi Heine borders somewhere between being good and just alright. It's a lighthearted character driven slice of life story, focused on self-improvement so each of the princes can become worthy candidates to the throne. The characters themselves are unfortunately fairly simple, but still have enough depth and charm so that I wouldn't describe them as being one-dimensional. All of the princes have easily memorable personalities and flaws due to this simplicity, so given the show is only 12 episodes long, being simple may be a necessary evil. The dialogue was kind of bland, I'm not sure what is was about it but it felt like what a character in a book would talk like rather than a real person. All of the plotlines themselves are also very straightforward and mostly predictable, but despite this it was all really wholesome, and didn't bother me all too much. To my surprise there's actually an underlying plot behind all of this, which was fairly enjoyable, although I would've preferred if there was a larger emphasis on world building as there seemed to be some potential.
The show's humor was decent; I don't think it tried too hard to be hilarious, just enough to keep you entertained. A lot of the verbal jokes were on a similar caliber to "look the tutor is short" and "that ostrich thinks you look like a girl," but I did actually enjoy a lot of the visual humor like when Heine turns into a pouty chibi.
On the technical side of things, if anyone actually cares:
The animation is good, although not impressive.
The art is nice, but the artstyle is fairly generic. There were maybe 2 or 3 character designs that made a good impression on me.
The music is fitting, but also fairly unnoticeable, and doesn't stand out as anything special.
Overall I say while it isn't a standout show in any regard, it's quite wholesome, and more or less enjoyable the entire way through (maybe with some minor cringe at parts). I don't recommend going out of your way to watch it, but if you think you'd enjoy a wholesome slice of life I wouldn't recommend against it either. 6.5/10