Wei is more MBA minded, and more American cultured, despite living in the US less than Chang, and not having a business school experience behind him. This is what was his undoing when Chang had to move in back to fix after the duo I believe.
At around first time Wei's first try as Co-CEO, he pushed for abstract "business performance" too much, while forgetting about what was happening on the ground (TSMCs 16nm-28nm train wreck,) leading to a mess-up a decade ago. Definitely a man who was conditioned to go after "new exciting things."
Not true at all. TSMC 28nm and 16nm were great nodes.
28nm was a big node for TSMC. TSMC followed Intel with the gate-last implementation and was the first foundry to 28nm. The others UMC, Samsung, Chartered, etc... did gate-first and did not yield. TSMC ended up with a record market share thanks to 28nm and that market share keeps growing.
The big problem with 16nm was the name. Intel and Samsung had 14nm and TSMC had to explain why 16nm different than 14nm. That name was chosen by Morris Chang as respect for Intel since their 14nm was more dense. Samsung called theirs 14nm even though it was comparable to TSMC 16nm. Now node names are mostly marketing and TSMC is playing that game quite well.
Morris Change leaving TSMC was a good thing, his time was past. I don't think you will find a TSMC employee that would disagree.