How can you forgot Portugal?
About your idea, I would prefer it's another name like Greater Carolingia or something like that. I don't sure if Franco-Iberia is a real faction name but it sound bad to my ear.
And there are hardly anyone who identify themselves as Franks for about a thousand years, but I think it's pretty much valid assumption
Franco - Iberia is confirmed name. Yeah it sounds stupid
BE takes place 250 years in the future when such things as POLYSTRALIA, confederation of Slavic nations or imperial corporations are apparently possible
So while I know there are no 'people' who identify with Franks... Wait, look - many empires in the history of Europe were built on Frankish legacy. Obvious one - France, but also Holy Roman Empire, Habsburgs... Even Napoleon returned in 19th century to the myth of Charlemagne.
BE developers didn't choose the boring obvious way of 'hey in the future Europe will be united as... uh... European Union 2.0'
but instead Europe is divided between Slavic Federation (the entire Eastern Europe, I guess) and Franco - Iberia. The name 'Franco - Iberia' IMHO signals some kind of 'return to the roots'.
Now, what are Western European countries going to return to if European Union has collapsed and nationalism is no longer possible? The universalism of Charlemagne seems plausible for me. Hey, this is the main pillar of European civilization (secondary pillars: ancient Roman Empire, Jewish religion, Byzantium, knowledge from Islam civilization - but those are not really possible in this case
)
There are two options.
1) Franco - Iberia is literally FRANCE + SPAIN + PORTUGAL
D ) and it is by far the stupidest faction of BE. Not only ~100 million people are somehow supposed to face such factions as Panasian Cooperative with ~1,5 billion people, but what exactly the cooperation/culture of these nations is based on? Uhm... Catholic Church? Huge problems with internal minorities?
(French muslims, Basque, Catalonia)...
2) Franco - Iberia is FRANKISH EMPIRE 2.0 as the new era of Europe. Countries united around the myth of Charlemagne and first European universalism. Also so far developers didn't reveal mandatory 'cultural powerhouse' faction - FI would fit here perfectly. France and Spain are the greatest touristic powers of the world today. The entire faction would make sense for me:
France + Belgium + Luxemburg + Switzerland + Austria + Germany + Belgium + Italy = Frankish Kingdom
+ Spain + Portugal = Franco - Iberia
Cultural powerhouse. Old good Europe, Western Europe. Legacy of Rome and Charlemagne. If this faction won't exist in BE I will mod it