My teacher teaches taiji the way he learnt it from his teachers (Grandmasters Lim Bo Yan, Hu Yunhua, plus Chen Xiaowang and Zhu Tiancai, though the latter two consider him contemporaries rather than teacher-student). He passes on the same taiji theory that his teachers taught him. He doesn't try to come up with his own theories, instead assimilating his own understanding into the theories taught by his teachers. He spent years learning taiji, and even more years practising what he learnt, as he learnt it. This got him to where he is today. His training is effective, as shown by his achievement.
There are some teachers who try to come up with scientific theories behind taiji. They no longer teach taiji as they learnt it; instead, they have used their understanding from their learning to derive their own theory, trying to base it on modern science to appeal to the modern student. In so doing, they hope to shorten the learning curve, to make training more efficient.
But is efficient training the same as effective training?
If I spend 30 years doing what my teacher taught me, I should be able to achieve close to what he did.
What remains unknown is whether using that same 30 years to train under a modern scientific method will yield the same result. After all, the person who came up with that method did not reach where he is using that method. He trained under his teacher using the good old traditional way.
One is a proven method. The other sounds right to the modern scientific mind, but is unproven.
To be effective? Or to be efficient? Can wit really replace hard work?