It might get more coverage if it happens that William and Kate attend.
That would serve to promote interest outside the UK and Spain.
(Bonus points if Harry shows up!
Television - Maybe outside the UK, but not inside the country. As I said in my post above, the BBC, ITV, SKY etc isn't interested in state visits with the exception of visits from the US and China. If they show anything at all, it will just be some clips of the Queen's speech at the state banquet.
Papers - The Fail, Express, and maybe the Telegraph may have pictures of Kate on their front pages to show her with a tiara or show her dress.
Papers websites - The Mail will have a lot of pictures as they usually have when it's state visits and will along with the other papers be interested in the Gibraltar issue and if the Queen and Felipe mentions it in their speeches.
Royal events the UK television/papers have been very interested in since 2000.
2000 - The Queen Mother's 100th birthday
2001 - The Queen Mother in hospital
2002 - Princess Margaret death (a bit)
2002 - The Queen Mother's death and funeral
2002 - The Queen's Golden Jubilee
2003 - The Queen in hospital two times january and
december
2003 - US state visit to the UK
2005 - Charles and Camilla's wedding
2005 - Chinese state visit to UK
2006 - The Queen's 80th birthday
2008 - Philip in hospital
2010 - William and Kate's engagement
2011 - William and Kate's wedding
2011 - The Queen's state visit to Ireland
2011 - US state visit to the UK
2011 - Philip in hospital
2012 - The Queen's Diamond Jubilee
2012 - Philip in hospital two times june and august
2012 - Kate's pregnancy
2013 - The Queen in Hospital
2013 - Philip in Hospital
2013 - George's birth
2014 - Irish state visit to the UK (not as much as the state visits from US and China)
2014 - Kate's pregnancy
2015 - Charlotte's birth
2015 - The Queen becoming the longest reigning
monarch in British history
2015 - Chinese state visit to UK
The next big royal television/papers event will be the Queen's 90th birthday next year.