Reb Eliezer, thanks, these are good ones, but not so much peshat..
my daughter’s suggestion – the brothers are not ready to accept Yosef as their Rebbe based on mutual history [and we see it later, when brothers insinuate Yaakov’s words to Yosef]
the only relevant explanations I was able to find – Lubavitcher saying that we should learn from Yosef in practical matters, but Yehudah is pure Torah. There are others who just laud Yehudah in a similar vein, without contrasting with Yosef. This is a little hard to accept as we learned before from Yaakov that one can be both a Torah person and deal with the world… Do we see anywhere that Yehudah paskens better than Yosef? So, it seems indeed that Yosef Torah is good, just students are not ready for it.