Good points:
+ Fun, unpredictable jokes - mostly present in the first half of the series, though. I was laughing hard at times.
+ Somewhat unique main hero, who has some bad points
+ Interesting way of storytelling (an uncle telling stories of his past to his nephew in semi-random order)
Bad points:
- Unlogical, simplistic plot - unfortunately, at its core this anime remains a typical isekai. Main hero travels around the world, does mostly random episodic stuff - fights monsters, helps people, etc. There are no prominent villains, no real challenge, nothing deep or smart in the story. This doesn't matter much when anime acts goofy and as a comedy... But later on it tries to invest into dramas, and those ended up being weak.
- Super powerful main hero - the anime seemingly is often claimed as an extraordinary one, but come on. Uncle never has any trouble with enemies, unless the plot wants to invest into one of the few other characters. So he is like a Onepunchman, who somehow gets disabled from time to time. Or like a Kirito, if you want. Again: absurd power sometimes works nicely with jokes, but it feels bad for dramas
- Harem with multiple girls and forced fanservice - this was present in almost every episode and took quite some time. Uncle was considered ugly, yet girl after girl fell after him? He is a nerd type gamer for life, yet he easily jumps on girls just to check wounds or make them massage and finds nothing wrong about it? Finally: he doesn't really feel or understand anything..? Fanservise was incredibly forced here: bad bad bad.
- Characters in 'real' world were exceptionally boring. They just sit there (like Big Yoshi). They stare. They judge, they scream, rarely - ask stupid questions. They become extremely predictable and uninteresting later.
Fun and expectations were high at the show's start, but stably drained down with time. The series is treading water: changes with time are minimal and unnoticeable and comedy transforming into drama made quite obvious many minuses, like simplicity of plot and almost everything. It feels like once again a story with a self-inserted author in a role of the main character. An ugly gamer focused only on games, then suddenly in another world he is an almighty mage-warrior, that girls hang themselves on like a hanger. At least he is somewhat funny, I must give that to him
Bonus: I also find it interesting of how many anime titles this 'unique' one reminds me off:
* Konosuba - obviously - for its humour and fanservice. That been said, Konosuba has deeper and brighter characters and heavily outclasses Ojisan, imo
* One Punch Man - for the powerful yet somewhat dumb main hero.
* Sakamoto-desu - for the unique main hero, jokes and, sadly, repetitive pattern - both those anime have better starting episodes than later ones.
* Sword Art Online \ Shield hero - later on Ojisan basically transforms into one of this.
* Dofus: The Treasures of Kerubim ('almost' an anime - french cartoon) - for the way of storytelling. In Dofus - old cat tells the stories of his youth and adventures, in Ojisan, well - an uncle does the same. Dofus, however, while being slightly more childish - was deeper and with much more likeable characters, so I would recommend it much more so than Ojisan.
All in all - Isekai Ojisan had an intriguing start and ~first half of the show where it was mostly a simple dumb yet fun comedy but falls heavily later, where it invests into cheap dramas, harem girls and fancervice. That's it.
