We talked about what kind of person we want to become in the future.
We discussed about what kind of person we want to be in the future.
話し合うは英語で talk about / discuss about といいます。「お互いに話し合う」というニュアンスを加えたければ、talk to each other about となります。
どんな人になりたい＝what kind of person we want to become
将来 ＝ in the future
in the future の他には、in the long run というフレーズがあります。こちらは直接的に将来という直訳ではないですが、長期的に、最終的には、という意味があります。なので、このシチュエーションでは使えます。
例：
We talked about what kind of person we want to become in the long run.
どうぞご参考に。
We talked about (discussed) what kind of person we want to be in the future.
We talked about the kind of people we want to become in the future.
At the meeting, everyone talked about the kind of professionals (workers/employees) we want to become in the future.
「将来どんな人になりたいか話しあった。」＝ We talked about (discussed) what kind of person we want to be in the future. / We talked about the kind of people we want to become in the future.
「将来、どんな仕事人になりたいかを会議でみんなで話しあいました。」＝ At the meeting, everyone talked about the kind of professionals (workers/employees) we want to become in the future.
ボキャブラリー
将来 ＝ the future
なりたい ＝ want to become/be
どんな ＝ what kind of
話し合う ＝ talk about/discuss
会議 ＝ meeting
仕事人 ＝ professional/worker/employee
日本 
イギリス 
