Don't mean to sound harsh, but...
This doesn't actually seem like an adventure to me. It's a series of disconnected challenges (some of which are not, indeed, challenging) set into a rather cliched WoW-like setting. By WoW-like, the universe seems constructed to create and offer interesting and profitable challenges to "adventurers" (which seems meta-game to me). It should be the other way around: the world exists, and adventurers try to perform useful tasks to make a living in it.
You don't give the players any choices other than solving a series of puzzles and combats. The penalty for failing a roll (such as dungeoneering in trial 4) or deviating from the path (by any interaction with NPCs short of following directions) is inevitably death. The NPCs, moreover, don't seem to have any motivation. Why is the guildmaster awarding big cash payouts for people willing to run a gauntlet?
The gauntlet itself is somewhat interesting as a concept, but there's no story surrounding it to speak of. In and of itself it DOES NOT constitute an adventure. If you want to salvage it, I suggest you add a section in which the players have time to explore the town, get the lay of the land, and "discover" this gauntlet challenge, rather than just being directed to it by a series of (literal) signposts and NPCs. The question I'm asking myself, over and over, is why? Why is this here? Why is it worth 500gp for people to go through it? Drop some clues while they go through it. Maybe the gauntlet is owned by a necromancer, who needs the bodies of those who fail to run his experiments. Maybe the gauntlet has no cash prize, but is merely the trial for entering a prestigious guild. (In that case, you need to show that the guild is prestigious, not just tell them: have some grizzled mercs running around town, disrespecting anyone who ISN'T a guild member).