I dont know the exact details but someone showed me a video and said that once you invest your points past 10 on one of them it lets you create unlimited items.  He used to create unlimited RPG rockets.  Before this plugin allowed you to research everything on the workbench for free using the same scrap.  Definitely stay away from this plugin until these huge exploits are patched.  But also consider that 3 of the trees are basically cheats that improve your PVP survivability.  A lot of people would quit your server knowing someone can evade a headshot based on a dice roll

The admin has complete control over what is and isn't included. If something is broken, they can disable specific parts. I wouldn't discount the entire plugin because a part is messed up. The dev is responsive. The admin of the server should be aware of this as well, so they can disable or alter anything that isn't a good fit for their server. 

Every option in this mod is adjustable. Depending on how you have the settings you can make this mod do anything or nothing. I would suggest actually trying it yourself and understandings how it works before making any comments on it.