I'm guessing that if they knew about the Telltale games, they wouldn't be confused by the 5-hour length.
Episodes are not standalone games, and they're priced accordingly. You may choose to wait until all episodes are available to enjoy the game as a single package. I hope that they localize each episode individually, because I personally don't have a problem with the episodic format; I prefer it to waiting long for a single game. In Telltale's case, the gap between episodes ranges between two and four months.
If anyone finds the game lackluster based on Serebii's coverage, you should realize that story-driven games need to be experienced first-hand. Serebii either didn't want to spoil much or the language barrier limited his understanding of the plot.
A bit of both. The plot is covered mostly in the section, but I don't want to completely ruin every line, every nuance, every twist etc.
I provide a resource, not a giant spoiler. This game is a Cinematic Adventure game, a large part of the enjoyment is in the way the story plays out and experiencing it that way.