The best way is making the new Big Bad stronger than the previous one. Thus they had two options, power down the heroes or power up the bad guys. Zenoheld was the next Big Bad, but had to be more of a challenge than Naga was to be intresting.
BAKUGAN BATTLE BRAWLERS JULIE SERIES
It makes sense that they would get a little better as the series goes on, but in the first season, a monster with a power level of 400 was considered a Game-Breaker, but now everybody's throwing around 900-level monsters like it's nobody's business. It really bugs me that the monsters' seasonal power boosts are ridiculously huge.And the fact that they keep getting rid of their regular Bakugan for a newfangled version is irritating.(Dan being the exception, of course) In the third, he played a more decent role, but wasn't important to the plot at all. Marucho is often times annoying(know it all), and Shun really doesn't add anything anymore. Honestly, most are fine with Dan, since he's the main hero. As as of Mechtanium Surge, everybody but the same three were bussed yet again.Why is everbody but Dan, Marucho, Shun, and Drago put on a bus eventually? (Odds are, Julie's going to get axed by the end of Gundalian.) Why still keep the guys the same as well? I mean, I know plenty of people that are quite tired of Marucho and Shun is.mostly just there now.
BAKUGAN BATTLE BRAWLERS JULIE HOW TO
I have no interest in ACTUALLY playing the game, but the anime never really gives a clear explanation on the rules. After watching the very first episodes of the series (Battle Brawlers), I can safely say that I have no idea how to play the game.Not to mention, a She's Not My Girlfriend Running Gag would probably get stale. Mushy romance stuff probably wouldn't sit well with the show's key demographic, and could potentially derail the main plot. It's possible that the girls were cut out of the show to prevent a romantic subplot from forming.
Maybe it has to deal with marketing, or thinking that young boys don't really care or identify with the females? (Which wouldn't be the correct thinking.)