He had some capability to fight the Taliban - but not enough to resources to defeat them. I posted several articles about Massood in the months and years prior to 9/11, and frankly, he was on his last leg.
Prior to his death, Massood went on a speaking tour across Europe, warning about the dangers of the Taliban and seeking military and financial assistance. He was warmly received in the European capitals - but he received no help. He was deeply disappointed at the lack of response. Only when the Taliban destroyed the Buddhist statues at Bamiyan did the international community begin to sense the evils of Talibanism.
A few weeks before his assassination, the Taliban launched a major offensive against the Northern Alliance. Massood was losing ground daily, and it was just a matter of time until his positions were lost.
If al-Qaeda had not attacked the U.S., the Taliban would have achieved total hegemony over Afghanistan by the Winter of 2001. But since bin Laden made the tactical error of assassinating Massood just a couple of days before 9/11, the Northern Alliance still had a small pocket of territory and enough fighters to effectively help the U.S. when our troops arrived in the following weeks. They were good allies.
So his death didn't have an effect on the part of history I am interested in.
That is good news, although as an individual he sounds like like an interesting leader that we would have liked to see fulfill his promise.