Well, the only thing I can think of is the amount of flow with the flow balance between the two sides and the amount in percentage vs each other.
A good question is really, can the head benefit from a larger valve? Ether side or both. How well does this head do In theory scientifically speaking with the flow rates listed? And against another head? Then in reality?
The head was designed with certain parameters in mind. Did it meet these parameters? Does it fit your build? IMO, for a OOTB head, it looks really good. For your personal build (you or anyone reading) it just needs to fit in with the program and goal. What can make the head better? I don’t know. Will a bigger valve help? More porting in the head? Is it worth it? What Head is next on the way up and is the price worth it vs modifications to the TF head?
Always a ton of questions to ask one self!