It's a difficult question to answer. Any type of contract like that takes on enormous risk. However, I don't find any of those contracts to be entirely unpalatable for 1 main reason:
in 10 years, is 35 million per year the going rate for superstars, or will it be even higher with increasing revenues? One thing that we know we can predict is that contracts #'s always increase over time, but the variable is... how much?
Paying Tatis 35 million dollars per year 10 years from now may not be that big of a drain depending on where the $ per Win calculation is at that time - unless he's not playing at all due to catastrophic injury.
That said, I wouldn't give Vlad that much. He's going to be a beast when he's young, but his fall-off-a-cliff value point is going to come much earlier due to his body type and the fact that he has virtually no defensive value already, let alone in 10 years.