The problem is, you can't go back and fix it. The characters are now there and they've gone through their first season. The only thing now is to plow ahead with some other storyline; and from what I've seen, the second (or third) runs aren't as good as the first. Given how shallow this one was, I fear the second will be pretty bad. This series really needed those 'filler' episodes to make us care about the cast. Take the first three angels, spend two or three episodes before bringing in the next one (instead of throwing her in in Ep 2, followed by 2 more in Ep 3, followed by...). Basically, they introduced themselves, we spent a few brief minutes watching them, then it was time for the next batch to be thrown in the group.
Well, there was the snake, and she turned out to be quite the looker...
And are all guardian angels girls? He didn't have a single male pet? And he couldn't play any other melodies on that harmonica? And why did they all think he was such a good master? Shouldn't the fact that a dozen DIFFERENT pets ended up dead under his care clue them in to something about the boy?