He is more of a "cheap" stop gap for the next 3 seasons than a proper Mkhitaryan replacement. We haven't found that yet.
Generally I would agree with you, but not in the particular situation where Inter is right now.
First of all, Mkhitaryan was supposed to be a stop gap, then we brought Zielinski, who should be a stop gap of a stop gap. Don't you see how ridiculous is that? Instead to find a proper replacement of Mhiky, we have another old player with lower quality. Then we have Arnautovic, Taremi, Acerbi and the oldest squad in Italy, or maybe even in Europe top leagues.
If we keep going this way, we can be much closer to another banter era instead of stay competitive on a high level.
"Cheap" is another thing which I want to discuss. If we speak about Acerbi and Mkhitaryan, that is valid as we get immediate starting material for a bit higher salary. But if those deals turn to a failure, like Arnautovic, Taremi and Zielinski, we end up with deadwood with no release value.
For instance, Taremi+Zielinski salaries are around 10mln net, while Frattesi and Asllani have less than 5mln net combined. We paid close to 50 mln in total for the latter, of course. But, we can sell them now for the same price at least, and to invest the money in someone new. With Taremi and Zielinski we cannot do that. They are deadwood. And we are heading to the moment, where we will be full of old "stop gaps" with no release value