Strange...there is no 5E Southland Campaign Setting (only Pathfinder), but a pdf for 5E?
I'm actually going to put myself out there and say Kobold usually does some very quality stuff. I find their World Building resources invaluable, and their mag Kobold Quarterly was fantastic. The people in that company are very good at what they do.
It's unfortunate, but the Tiamat stuff was being worked on while 5th edition was still in development, which kind of threw a wrench in that book. You are right in that they definitely have a handle on Pathfinder stuff more so than 5e stuff from the looks of things, but I definitely encourage you to not overlook them.
The werelion can assume an animal form (a panther) swapping their statblock like wild shape, but retains their hit points. Which sounds potent but might not be that amazing in play. So I'd want to see it in action.The races aren't overpowered except for the werelions which are "Close enough". Could you expand on what is or isn't unbalanced?
The real concern is in the subclasses. Here the risk of powercreep is acute.
Annnnnnnd it's been pulled! That didn't take long.
Huh-- I was hoping to see how they did Gnolls and Lizardfolk. Those are things WotC hasn't tackled and may not tackle for a very long time.
I was hoping to get my copy on Friday. Maybe it'll be back up soon?