>>33123675Clair has a pretty notable level jump, having Pokemon all 5-8 levels higher than Jasmine, Pryce and Chuck who are all fought very closely to each other, and thus have minimal level differences.
Thing is, Clair's also fought rather quickly after you deal with the other Leaders and disbanding Rocket, but unless you've been actively grinding the average team of six will probably still be in the Early or Mid 30s since Team Rocket rarely uses anything other than unevolved fodder that hardly gives EXP.
Most Level Curve complaints in regards to Clair are ACTUALLY directed towards her Kingdra, who has great stats for that point of the game and no weaknesses aside from Twister unless you honestly went out of your way to grind a Dratini into a Dragonite who knew Outrage.
In HGSS, your other options were to grind a Seadra until it learned Dragon Pulse or get lucky on the Lottery for TM Dragon Claw.
The curve calms down after Clair a bit, but the E4 gradually goes up from Pokemon in the early 40s to Lance's late 40s.
Then the complaints come back in regards to his trio of Dragonite, but it wasn't nearly as bad since they actually had an attainable weakness.
Kanto was mostly filled with trainers of all levels but nothing above 40 aside from jokes like Magikarp, Gym Leaders varying between 40-50 aside from Janine, and then Blue who comes just short of 60 in GSC.
Lastly, there's the gap between Blue and Red which everyone knows at this point.