Nothing… well… Grit now I guess giving them armor as their “protection” stat
I think you don’t quite understand what @Jimbo means by that when he says it… it has a very specific context to it…
And that’s pretty much it… that context matters… and you need to set some parameters by which you want to rank things for there to be a “best”…
So no… there is not “best” thrall universally… because I might be suggesting you an RHTS when in reality you want something to put in an armorer bench… or to dance and remove your corruption 
both of which for the RHTS is absolutely useless…
BUT… if you’re looking for the best fighter thrall template to start out with… who objectively has the best combat-balanced stats and has the best chance to turn out to be the better fighter, then that’s it…
I am going to point out something and I need you to try and understand it… I’m not trying to be mean 
Your anecdotal experience means absolutely ZERO…
I know that you’ve been playing this game for a long time and know many cool tricks and tips That’s not what I’m talking about here.
A lot of things that you have experienced in the past though have either been changed by Funcom with or without your knowledge, and lot of other things were never like you thought in the first place since you judged them based on the momentary “feel” of it… and humans aren’t the most reliable instruments for objectively measuring things…
So when we have actual numbers and facts to back something up and I can go ahead and measure things completely objectively (like I did with your thralls when you said your purge archer outdamages a Dalinsia and has more health regen), without having to rely on my personal feelings… - in these types of questions that’s what matters… and not the anecdotal thing you might have experienced at some point in time that you yourself can’t even explain 
Well the last such case turned out to be Charles with his Teimos and while he certainly did not lack enthusiasm… I wouldn’t exactly call him a reliable source…
Despite all that though, I always make sure to mention that regardless of what numbers and data say… the goal is to have fun and enjoy the game. So you can use whatever thrall / weapon / build you feel like and you don’t have to explain that to anyone
What me and others are trying to do though is correct misinformation as much as possible, that’s all, we’re not saying don’t use this or that…