Blaine
Skeletron
The facts are, the segment multipliers were raised. You're absolutely right in that it's not as strong as it was if you have a minion count of 1, but for a summoner that would actually use the dragon as a main killing force, it's much better. Cells outperformed it before, it was worthless as a main summon compared to its sister weapon.
But I guess it's ruined. Nuetered and garbage, according to some particularly salty posts. ...Kind of like how Phantasm and it's immense 15k-ish DPS was utter trash last patch.
Yeah, I just saw @Leinfors post; seems I guessed right. It wasn't a hard guess, because I noticed how strong just one segment was as a non-summoner when I first got my the staff. It's been nerfed at very low segments, somewhat buffed at high segments.
What I like to do when actually playing summoner is to mix Cells and the Dragon, because as strong as the Dragon can be (it also has more range, and isn't hampered by nearby blocks), it's also just one minion, isn't nearly as fast as the cells, and the more enemies there are, the more rushing about it has to do.
Sounds like if I mix Dragon/Cells 5/6, it'll be at least as strong as before, possibly stronger. Can't complain too much about that.