Satoshi's character development was necessary as the show progressed. He couldn't remain the overconfident little dimwit he was in the early Kanto era. I can't even begin to envision the Houen era Satoshi doing some of the things that Kanto era Satoshi did (sending Kyatapii to fight Pidgeon, not catching on to who Natsume's father is, getting so many badges through pity, etc.).
Haruka may be the novice now (or at least she was when AG started), but at least the writers didn't baby her the way they babied Satoshi. If she lost a contest, then that was it - she lost that contest. That's one of the positive qualities of "Advanced Generation". The writers have not only devoted themselves to fleshing out the characters more, but they want to try their best not to screw up those characterizations. Satoshi got a lot of badges in Kanto for proving his bravery or devotion rather than winning a battle, and that kinda hindered his skills as a trainer (hence, why Lizardon wouldn't listen to him and ultimately cost him the Indigo Tournament). Haruka doesn't get a chance to earn a ribbon for free, and that makes her realize her coordinating flaws and try to fix them. [SPOIL]Granted, she lost the Grand Festival too, but at least it wasn't due to her ineptitude as a coordinator - she was just up against opponents that were stronger than her.[/SPOIL] Satoshi's previous mistakes aren't those of Haruka.
Wow, that really drifted off-topic towards the end there...I guess once I get going, it's hard to stop.