The recall for the Corolla HB's CVT trans was not related to any issue with the design of the trans itself. It was a production issue which involved the torque converter. In addition, the trans used in the Corolla HB is not the same as our trans. It has a physical first gear which they refer to as the launch gear. I wouldn't draw parallels to that recall and what is happening here.
While it's disconcerting that there are two reported issues with the CVTs used in our cars, I would want to know what exactly is the issue. Plus two out of the thousands of trans' out in the wild isn't predictive of the overall reliability of these trans'.
On the BMW motor. Barring some unique design quirks of the B58 motor, I wouldn't be so quickly dismissive of it either. I have the previous generation N55 motor in my 2013 BMW 135i. Other than the annoying smaller issues, the car has yet to have left me stranded or has had any catastrophic failures in my 6 years of ownership with 97,500 miles on the clock. I also had the factory PPK tune done about a year into owning the car and then a couple of years later had the Dinan S2 tune done. The two repairs I did which are known issues on my N55 are the oil filter housing gasket (OFHG) and the electric water pump. The OFHG failed on my engine and started pissing oil all over the front and bottom of the engine. It's an annoying issue since the design is the same across the inline 6s (naturally aspirated or turbocharged) of that generation of motor: N51, N52, N54, N55, etc. The water pump was replaced proactively as it's known to go bad eventually and does so without warning which will put the engine in limp mode. I did mine at 75k. Some have pushed their water pumps to just over 100k before failure. But the B58 resolved the water pump issue because it uses a mechanical water pump now. Oh and BMW finally got a clue and added an oil dip stick back into the motor. The B58 has been proving to be a pretty stout motor as many tuners are getting some pretty good power numbers from it. Papadakis Racing who are known for their 2JZ motor builds has been neck deep into the B58 when the new Supra came out. There are Youtube videos they have where they've built out a 1000HP B58 motor. And the ZF trans being used with the B58 also seems to be pretty reliable.
Personally, if I was in the market for another sports car, I'd seriously consider the new Supra or the M2C. The Z4 is out of the running because I don't want a convertible.