I love Jiri, and I'm no MMA technical expert, but man alive I get the sense he has zero striking defence beyond having his long arms always in your way. Even in this video, he looks so hitable.
I agree with the Tony-of-LHW comments. I think Jiri is gonna fall off a cliff when he starts to slow down a little bit.
There's something very entertaining and quite succesful about the totally-unique and intense styles that guys like Tony and Jiri bring to the table, but it is absolutely rooted in physical talents like speed,timing and maybe most importantly, chin. Once these start to diminish even a little bit, it seems, the falloff is severe.
You can't help but wonder how much better these kinds of guys would do with a more traditional, more-defensive-minded training regime.