Fyrwald has been appointed because he is American, in the hope that this will help convince the CFIUS / USDA / FDA that new Syngenta will be the same as old Syngenta. That's an ambitious hope, because Syngenta will undoubtedly change dramatically, and quickly. The focus will be on bringing existing corn and soy technology to China, on running the business for cash elsewhere, and on migrating manufacturing and other activities to China. There won't be much cash in the new Syngenta for new product/trait development, or any other investment. The US business will undoubtedly decline, and for every dollar lost in the US/Canada, they will need to make an additional three dollars in China to even match existing profitability.
This is assuming that the Chemchina deal actually goes through, of course! There's an increasing school of thought that this may not happen, and that Syngenta has gone through an elaborate facade in order to buy time. Why on earth would you want to carry such a large amount of debt, and suffocate the business as a consequence? Now its competitors are doing less well in difficult markets, and there may soon be the prospect of an industry merger, on Syngenta's terms.
Monsanto's continued interest in Syngenta now being reported by Bloomberg and Reuters. Continued silence from Syngenta, but Fyrwald can see an opportunity to do a much better deal, secure a decent role for himself, and lose the serial underperformers. Main question seems to be convincing Chemchina to back off without losing face. A large manufacturing deal, and distribution deal in China, may be acceptable compromises.
Over the weekend, the Swiss press has been reporting on the CFIUS refiling, and the need for more time. Their interpretation, including some input from 'insiders', is that the negotations with the US authorities are going nowhere, and that the deal is quite likely to fail. The silence from Syngenta is probably a strong signal that there are problems; I guess we'll know fairly soon, one way or another, but the share price discount to the offer price makes it clear what the market thinks.
An industry merger would make more sense anyway, and it's possible (probable?) that Monsanto seeks to escape Bayer by making a formal offer for Syngenta, somewhere in the CHF450 range. Syngenta board and management have lost all credibility, and would be unable to mount any persuasive defence. Monsanto simply needs to wait for the Chemchina deal to unravel, so that it doesn't have to pay the break-up fee. This could easily happen within the next few weeks, but the share price will be extremely volatile, probably in a CHF350 - 420 range.