I hate that too, its just an unecessary pillowfight between 2 lame champs.
I just feel like challenges are so much work (to move models, resolve what happens, etc.)... if theres a challenge it should be between Archaon and Karl franz, not my sergeant and your Daemon prince.
There should just be less challenges. If you want to hit a character, do it.
In fact what if you had no challenges at all but you HAD TO target your attacks against the models that attacked you.
So this means whoever has the highest Initiative gets to decide who is fighting whom. If I am elves, my spearmen attack your ogre character. That character will probably live, but why can he just ignore their spear points and walk on over to my character and bash his face in?
And how come everyone fights with honor? Once you are in a challenge you can only direct your attacks at your partner... well why wouldnt you do some damage to other nearby guys if you felt like it? We already established that you can walk off some spearpoints and such and go attack whoever you want, so why not now?
Its just arbitrary and frustrating to me