SPOILERS so...
Finished it over the weekend. I liked it better than 2, which dragged a bit at times - but I think the next season should definitely wrap up the story. While the characters' stories are evolving, the overall plot is hitting the same points as the previous 2 seasons (monster of the week, portal needs closing, evil scientist). The reveal at the end that 11's powers may be gone/weakened is a welcomed twist, which may help next season start to veer off from the familiarity of her always saving the day; and also help the characters work on other ways to win instead of the answer always being "Just have El take care of it".
As far as the other pros and cons of this season...
I loved the performances, the visual style, the soundtrack. Anything from Scoops Troop was fantastic and I really loved the twist with Steve and Robin, which was handled well.
I think Nancy and Jonathan's storyline was the weakest, and worst part of this season. It seemed the writers were just finding a reason to have them included and it definitely felt forced. I think their roles should diminish next season if they can't find a natural progression to the story for them to fit in.