That depends what you mean by teething problems. If the engine is totally knackered at 70 000 miles, is that a teething problem ? I am certain that I have read Burnerman say on here that bearing housings (?) are made from plastic ( forget which engines). Is that correct , John ? If that is the case, then the engine has been designed in the full knowledge that it will die at a relatively low mileage.
If, however, all manufacturers take that route, it will become the norm as there will be no choice, however I have to say I would never for one second consider buying a Mondeo powered by a 1.0 l EcoBoost engine ( 2015-2017 ). It would seem beyond all stupidity to have such a small engine hauling around such a large car and expect a good life from it.