While I'm glad Sanderson finished the series, I still felt there was a pretty strong change in the feeling of the story.

Until he took over, Rand was basically continuously loosing his sanity in the pursuit of power, which he needed to fight the dark one, which brought him closer to the madness, feeding the cycle.

It kept getting more urgent, things kept escalating. But Sandersons Rand never really lost control, imo. Rand's success felt preordained by his story telling, whereas previously the only thing we could expect was that Rand would go down fighting.

To be clear, I'm aware that Sanderson finished the story via Jordan's notes. But I strongly suspect he wouldn't have kept to them if he wrote it himself. I base that opinion on the fact that the series was supposed to be way shorter. I don't remember the exact number, but it was something like 6 books

Brandon Sanderson only wrote the last book though? (which he split in two because all the stuff Robert Jordan wanted to cram in would have been a ridiculous 2000+ page tome) so it was already going to be at least 11 books by Robert Jordan. FWIW the two Sanderson books are my favourite of the series (but they are also the ending so it's hard to say)

He wrote the last 3, which was indeed meant to be 1 by Jordan.