Regardless if Shaqiri is good or not, losing him to Inter is pathetic enough. There are tons of other examples.
All one had to do to see how good he can be was watch the world cup. He can be brilliant. He can also be very mediocre at times, as evidenced by his play with Bayern, hence the very low price tag, but I take his Bayern play with a grain of salt, considering Pep doesn't seem inclined to use him. So he may turn out good, he may turn out average.
He's being sold for around 15m. We paid around that for Pereyra FFS. Shaqiri is twice the player Pereyra, and he's much more suited to providing versatility for this team. Aside from that, if we brought in Shaqiri while Pereyra is here, we'd have two players who can play winger in attack as a somewhat natural and familiar position. We'd be able to use wing-based formations if we wanted. Shaqiri can also play AM, as seen by his play for his national team. 15m. To pass up that deal, after buying Pereyra in the summer for the same price is ridiculous.