I'm pretty sure the new tribes are the Sahagin and Kobalds anyway, so I'm going to talk like it's them.
First and foremost, I'm really excited to see the Sahagins finally come into play. The only time I've ever really been in their zone was for the CT FATE and the Scholar relic quest, when it's probably the most interesting of them all IMO. And on a semi related notes, I kinda find the Kobalds cute in a weird way (must be Suidoken's fault XD)
Let's talk about rewards though.
You know how Sylphs give Weaver stuff, and Amall'ja give Armorer stuff? Well what kind of crafting materials would these two tribes give? The Kobalds are miners and stuff, so they can give ores and ingots, but I can't remember if the Ja have those too or they have plates and stuff (since I focused the Sylphs for the Goobbue). The Sahagin... Well... Maybe cooking mats? God knows Culinarian is miserable to level.
Dyes are dyes, I don't think it's worth discussing too much.
Now, mounts. I love mounts, I am all about Vanity items. What kind of mounts can they possibly have? If we're basing mounts off of enemies that exist in the game already, than the Kobalds should get a giant Coblyn! Think about it... A rock spider... Miners... Can get a Coblyn minion from mining... It works! You can sit atop its rock, maybe your character will be clutching it to hold on maybe? Could be very interesting.
Now, the Sahagins... Again, it's hard to say anything about them since they're so absent from the story. I honestly have no idea, but I do know my dream is a giant floating shark.
And of course, the cute adorable minions <3
What do you guys think will happen with these quests?