4 weeks in Europe - Portugal/Spain/Italy itinerary

Hello! I am looking for feedback on my Europe trip itinerary. My plan is:

* Lisbon (3 days)

* Porto (4 days)

* Madrid (4 days)

* Seville (3 days)

* Granada (3 days)

* Barcelona (2 days)

* Rome (5 days)

* Florence (3 days)

* Milan (2 days)

I’m looking for any suggestions, such as:

* should I spent longer or less time in any of these cities?

* is the sequence of the trip going to be workable?

* have I missed anything??