Dear Ujm,
Understanding the Torah is critical to the fulfilment of the mitzvah of limud hatorah. My question is why is your hypothetical student, spending his whole day on what he does not understand? Better he learn something that he understands. Or else he can just learn Arizal or the Ragotchaver all day. Sitting all day on what you do not understand is also bittul torah.
Rewarded does not go by minutes or results. I do not totally disagree with your point. But it does not prove yours.
I don’t know what’s better for the yeshiva. However, the more the yeshiva prioritizes the one who follows the yeshiva guidance, over the one who is really growing in Torah- the more of a failure the yeshiva becomes. If a yeshiva can’t produce boys that are using their strengths for Torah, than why does it exist?