Well, I'm probably going to be the only one posting in this.
It's slice of life so people can just pick it up from this season, but they won't enjoy it as much if they haven't seen at least the first season because there's a lot of jokes they won't find as funny. It's made to appeal to fans who've watched the previous seasons more, though that's obvious.
Episode 1
I seriously had tears in my eyes when the opening theme came on, it's so Minami-ke like and I loved it, it was really nostalgic for me.
This episode was perfect and I loved all the inside jokes if you've seen the other seasons. All the characters still have their amazing personalities, though they made Haruka seem more of an airhead in this one, which is better, because they made her a bit of bitch in Okaeri. It's the good old Haruka people know. And Chiaki and Kana were amazing. I can't wait to see Hosaka. I didn't think I would like this animation that much but I think it's pretty nice, I liked it in Omatase as well. Of course I still wish for the first season's animation, but this is the animation style of today.
I'll definitely be watching the entire season and it's already on my Top 5 of this year and it'll stay on there for sure.
Also I've edited the opening post with the OP theme.