Yaakov had learned "the hard way" what his discrimination of his sons leads to.
The Gemmorah (Shabbos 10b) rules that:
"... אמר רב לעולם אל ישנה אדם בנו בין הבנים שבשביל משקל שני סלעים מילת שנתן יעקב ליוסף יותר משאר בניו נתקנאו בו אחיו ונתגלגל הדבר וירדו אבותינו למצרים":
... Rav said: A person should never distinguish one of his sons from among the other sons by giving him preferential treatment. As, due to the weight of two sela of fine wool [meilat] that Jacob gave to Joseph, beyond what he gave the rest of his sons, in making him the striped coat, his brothers became jealous of him and the matter unfolded and our forefathers descended to Egypt.
Nevertheless, Yakov [does not learn the lesson and] when blessing his sons uses vastly different languages:
- Yehuda gets a very lengthy prise and blessing.
- Reuben, Levi, and Shimon got scolded.
- Others get statements/blessings of different length and "depth" - some relate to the whole tribe and some only hint to one renown descendant.
Although we don't see additional fights between the brothers after those blessings, I still wonder, why the blessing differ so much?