While Efren may have enjoyed his best execution skills early in his career, his conceptualization skills grew considerably in the 1990s as he began to embrace the fringe games, especially one pocket and eight ball, but also bank pool and straight pool.
In my opinion, he was a much better pool player in the late 1990s than in the late 1980s.
At rotation pool, he never had a great break and the advantage he enjoyed as the world's best kicker was reduced by the advent of the jump cue. By the late 1990s, almost everyone carried one.
Any suggestion that Efren's prime ended in 1985 is, to me, absolutely ridiculous.