As another fellow Spaniard, I disagree. I mean, I would love if civs would get pick out of historical significance (which in this case, Spain would be a "vainilla civ" type of civ), but that's simply not the case due to a lot of different factors:
- Spain has a small PC gaming market (exhacerbated due to rampant piracy, let's get real here)
- Lots of European civilizations already cluttered around the same geographic area
- You need a solid religious and exploration system if you truthly want to get the best gameplay possibilities for Spain, and that's not present in most of the initial Civ releases
That being said, an Isabella with a "Reconquista" agenda might very well be a really fun civ to play with / against! Same goes for Charles V and his "Universal imperator" agenda. Who knows, perhaps we might get Spain in the main roost thanks to the inclussion of religion & exploration right out of the bat.
That being said, let's continue with the "non standard" types of often overlooked civs here. There's a particular area that the Civ saga has usually neglected: Eurasia. Huge territory, little popullation and zero actual geopolitical weight have damped the representation of this are in the saga, but once you start to scratch the surface there are many fascinating civilizations and opportunities for game design right there:
Eurasian region civs
Khazars
Nomadic peoples that latter became the second Jewish state to ever exist and that dominated the trade with the Bizantine empire and the silk route. What is not to love?
Gameplay aspects: Well, faith bonuses would be in order, as well as the ability to integrate people from many ethnicities into their empire. Oh, and their Qoruq should ought to appear in some form too! (a hidden mausoleum for their Kings, consisting on an underground palace built with subterranean rivers diverted into it!).
Harappan civilization:
Ancient culture that used to occuppy modern day Pakistan-Afganistan area, its legendary status almost rivals the one of Atlantis. Outstanding planned cities, far more advanced than any other metropolis of their time, and a quasi-utopical social order with little to no recorded warfare nor strife bodes well for some of the most puzzling lost civilizations ever.
Gameplay elements: They should have some kind of bonus for building districts, seeing how well planed their cities were. Some kind of diplomatic / city state bonus ought to be in order too, seeing how they were able to downright prevent war during the majority of their long timed existence.
Khazak Khanate
Comprising a huge landmass, the Khazak Khanate could easily be considered the precursor of modern Khazastan. Its culture combines its warrior past with a nomadic tradition of hospitality and religious syncretism that makes it unique.
Gameplay elements: The heavily nomadic Khazak culture could be represented by either longer land trade routes and perhaps even by some UA that allows for moving cities. Its recent history of its 100% artificial capital, Astana, could bode well for some type of late game district planning mechanic too!