I understand your reasoning. And I would fully agree for a trip around Christmas for instance. But not for Easter.
I personally try not to be in Barcelona for Christmas for instance. Shops are closed, but on top of that it's also a difficult time to get into restaurants (closed or reservations only). But Easter in Barcelona is nothing like that. It's basically just another Sunday.
I have not been in Madrid on Easter Sunday, but I cannot imagine it being very different.