I wish people would stop making decisions about important matters when they're drinking.
I wish people wouldn't make up their minds about important business matters at an Izakaya after work.
この場合、次のような言い方ができます。
ーI wish people would stop making decisions about important matters when we're drinking at bars.
「酒の席で重要な案件を決めるのはやめてほしい」
to make decisions で「決定する」
important matters で「重要な案件」
ーI wish people wouldn't make up their minds about important business matters at an Izakaya after work.
「仕事の後、居酒屋で重要なビジネス案件を決めるのをやめてくれたらいいのに」
to make up one's mind で「決断する」
important business matters で「重要なビジネス案件」
ご参考まで！
カナダ 
