Fantastic location - the best place to stay in Barcelona. Clean and ironed bedding, a lot of clean towels, swift response via phone, stunning view, lovely balconies and elevator.
On the improvement part there are also few things to share:
The necessity to sign the contract in Spanish, provide credit card and passport details and leave a deposit apart from airnbnb verification I find quite uncomfortable though this has been mentioned in the listening (if you scroll all the way down). There is no clear process of checking out confirming that there were no damage. The support is arranged by a rental company, so the idea of airnbnb seems a bit lost. The contact person upon every request gave a speech about what airnbnb means (e.g why I can't leave luggage after 11am) at the same time regarding deposit and contract process referred to practice in hotels :) Apartment feels a bit smaller than in the pictures and there was smell. The bathroom door can't be locked.
Make sure you bring your own soap, shower gel, coffee, tea and etc., but there was one roll of toilet paper on the bright side.
In any case these are minor things and we had very pleasant stay.