This topic may/will have pics to fit it and as such, feel free to add your own to the galleries of each season.
These are the following reasons I have come up with:
Most episodes in the first season were fun and happy, but there are some exceptions.
The two dramatic episodes were way at the end when Onpu Sacrificed herself and was put into a coma. However, she ends up waking up the same episode near the end.
I feel as the girls are still just eight year olds, the creators thought it'd be bad to already load on the drama. Perhaps maybe the viewers are growing with the girls. So they wanted to take such events slowly.
This season earned a little bit more drama then the last. The girls dealing with heartbreak, handling a baby, possible death, and characters trying to harm them/make them fail.
- They're just nine year olds and they have to learn how to handle a baby. Said baby goes missing plently of times, had trouble with her exams, and gets sick at the drop of a hat.
- Oyajide tries to kidnap Hana-chan and is willing to do what he has to in order to get her. Even mentally scar the girls.
- The ojamajo each had been given male counterparts but Doremi was the only one truly affected upon the reveal that they were evil, since she was the only one who felt something for hers.
- Trying to save Hana-chan, the girls sacrifice themselves; only to wake up after a course of five minutes.
(Gallery to be added later)
Death and grief play a big role this season, as a new ojamajo arrives.
Traumatization over said death if often brought up. Nothing dark, but a lot sadness.
Drama in making friends with the other ojamajo, racism, extreme social anxiety are also present in this season. Momoko ticked off both Hazuki and Onpu in the same episode, which isn't easy to do. However, this is fixed in the same episode.
(Gallery to come later)
- This season went from being a happy fun time to depressing and just a bit heartbreaking.
- Everyone is leaving each other which means they will no longer be a group OR ojamajo anymore. This causes more problems for Hana-chan, Hazuki, and Doremi near the end.
- Although it wasn't really that sad in feeling until nearing the end, the fact the series was over meant they had to make a big finish. Always dramatic.
(Gallery to begin later :3)
- This season in total had three drama based episodes
- Baya's love who is suspected to be dead as he vanished.
- Non-chan able to become a ojamajo dying the very night she was given permission
- Fami-chan coming to see Doremi as its implied Doremi isn't alive during her time anymore
- This season also had subtle dramatic moments: Onpu's episode is somewhat this, another Onpu episode has everyone thinking she lied, Aiko's long lost friend arrives, Hana-chan and Pop being jealous of each other and end up switching bodies... and so forth.
(Gallery to come later.)
So yes, this is why I think Dokkan may be the more depressing/dramatic season. While the others may have more sad moments and drama between characters. I feel the whole, leaving friends you've known for so long may be the most dramatic thing to someone. Its hard to imagine what would have happened, Had Hana-chan or Doremi were persistant in not allowing this to happen. Forbidden magic maybe?