I think 40 million is still too high considering his statistics which are not impressive enough during his time with Juventus but maybe things will change elsewhere and Vlahovic can show his extraordinary talent later with Aston Villa but the problem is not about the price tag but his salary which is quite high. Aston Villa must consider it very carefully because Vlahovic could fail to give his best performance in the Premier League.
It's still better.
Vlahovic: 29 matches, 10 goals, 4 assists, 40 Million Euros.
Nunez: 30 matches, 5 goals, 2 assists, 60 Million Euros.
The strategy to sign a high salary player is only sign for 1-2 years, if he play good, it's as expected. If he play bad, Aston Villa won't loss too much.
Teams are now making smarter contracts in this regard. Instead of long-term contracts like before, they prefer shorter contracts. This makes it easier for a player to be released from the team if he is not productive. If they want to send a player who has signed a four-year contract in the first year, they have to pay the remaining salary for three years. However, if they sign a two-year contract, they can pay an extra year's salary and release him from the team. Therefore, it makes more sense for teams to make transfers on short-term contracts. Also, if we look at the statistics, I think some players are overvalued.