The Pokemon Anime is suddenly awesome.

All pokemon battles aren't as brutal as that one, it's just that lucario gets A LOT more aggressive when mega evolving... Just saying.

While that is true, brutal battles are becoming more common, the previous episode had a pretty brutal fight between Blaziken and Lucario. And every Mega Evolution battle so far has been amazing.

In regards to the filler episodes, there is really no way to avoid it. It's a show about travelling through the pokemon world and encountering stuff. If they cut out filler episodes Ash would get from one gym to the next in like 2 episodes and wouldn't get any training.