I have a few leaders I would generally like to see, and then also a major remark regarding the inclusion of Denmark:
France -
Louis XIV
Spare me the Napoleon fanboys. The Corsican viper represents a set of revolutionary political ideas rather than France. Louis XIV, on the other hand, is one of maybe only two individuals - the other being de Gaulle - to have actually
been France. Louis XIV defined the latter half of the 17th century, and he is a definitive figure in French history that has not been present in a Civ game for decades. Furthermore, the 17th and early 18th centuries are generally rather underrepresented in Civ games. I would like to see more leaders from that time period - not the least as it is the one that I am personally most interested in.
Louis XIV could be a civ focused both military power and on culture.
England -
Pitt the Elder or
Pitt the Younger
I think it is time that England be represented by a prime minister (or First Lord of the Treasury in this instance, to be pedantic) rather than a monarch. I especially think Victoria was generally an awful choice for England in Civ 6, and I would much rather have seen an iconic figure from her time period that actually wielded power, who wasn't widely disliked, and who didn't live completely withdrawn from the public for the last 40 years of her life - i.e. one of his prime ministers. Disraeli or Gladstone would have been obvious choices. For Civ 7, however, I would much rather see a Prime Minister from a somewhat earlier period - either Chatham or his son, Pitt the Younger.
The two Pitts both afford Civ 7 the possibility of presenting a different type of England, as well as showing off England in a new time period. We haven't ever seen a 18th century England in a Civ game before, and Chatham in particular would represent a more military-focused and domination-focused England. With Chatham as leader, it would be possible to especially lean into the 'Rule the Waves' part of English history.
Germany -
Otto the Great or
Konrad Adenauer
My first thought was Frederick the Great, but then it suddenly hit me that I was about to suggest perhaps a few too many domination-focused civs, as well as four civs with leaders that were at the very least alive during the 18th century, even if they did not rule at the same time. I am also not entirely happy about suggesting the King of Prussia as the leader of 'Germany', although I think that Frederick the Great is so symbolic a figure that he, despite only being the ruler of a part of Germany, would be suitable enough a candidate.
As for other candidates, I think Otto the Great would be a good alternative. He was the ruler of all Germany - not just a state inside it. Him as leader also means that Germany could be made into a different type of civ this time. Otto the Great could lead a Germany focused on religion. Perhaps something relating to the reformation could be the country ability, and something relating to religious diplomacy or defending one's own religion could be the leader ability.
I have grown to quite like the idea of Otto the Great, but I would also be very pleased with Konrad Adenauer as leader. Adenauer might also be particularly suitable since we had a medieval Germany last game.
Russia -
Peter the Great
Peter the Great is one of my favourite historical characters, and he is one of the definitive characters in Russian history. I really would like to see him re-appear. Give him abilities similar to the ones he currently has in Civ 6, although perhaps with a little extra focus on maritime affairs, like shipbuilding an naval technology. I hope Civ 7 will make navies matter more, and Peter the Great would lend himself well to a Russia with a tiny bit of naval focus.
If it can't be Peter, then I wouldn't mind a medieval Russia, as has been proposed earlier on in this thread.
Denmark -
Christian IV or
Peder Schumacher Griffenfeld or
Frederik IV
It has been said in this thread that Belgium is the last major, historically important European country never to be given a civ. However, I would like to contend that Denmark too has never actually been represented in a Civ game. The Denmark of Civ 5 was merely a re-named, generic Viking civ. While Denmark has had to live with a completely generic abilities - with little connection to actual Danish history - Sweden, Denmark's historical nemesis - has twice in a row been made into an actual, historically-based civ that isn't just a base, somewhat insulting and tired regurgitation of American pop-history perceptions. To add further insult to injury, Civ 5 had Harald Bluetooth - a king who is mostly famous for converting Denmark to Christianity - talking about old Norse gods in a horrible modern accent.
Denmark has historically been a very important power in Europe. I am happy to see that some people in this thread have suggested a medieval Denmark under Margrethe I, which would certain also make sense. Denmark was the principal power in the Baltic during the medieval period, and another very strong contender for the leadership of a medieval Denmark would be Valdemar II
'the Victorious'. Valdemar's Denmark would be a crusading civ, though perhaps focus could also be drawn to his lawmaking efforts in some way?
However, personally I would quite like to see a 17th or 18th century Denmark. There are a couple of candidates for such a Denmark. One - the most obvious one - would be Christian IV, who is hands down the most famous and best-known monarch here in Denmark. He could head a commercial-maritime civ, possibly with some religious or cultural focus thrown into the mix as well. Two favourite alternate ideas of mine are for Peder Schumacher Griffenfeld, Christian V's extremely powerful minister who penned the
King's Law that made Denmark the most absolute of the absolute monarchies in Europe, as well as Frederik IV, probably the best of Denmark's absolutist kings.
Griffenfeld could have a leader ability relating to the Gottorp Question, which dominated Danish foreign policy for most of the 17th and 18th centuries. This could mean giving him a bonus / incentive towards conquering city states, as well as establishing order / loyalty in them. Something like a big culture boost from taking a neighbouring city state would also be apt. This leader ability would also fit Frederik IV, but Frederik IV could meanwhile also be the leader of a religious-commercial civ, focused on trade and colonisation. Frederik IV was the king who sent
Hans Egede to Greenland, and his leader ability could therefore fittingly be something relating to this endeavour to re-colonise Greenland. If a governor system is introduced in Civ 7, then perhaps Hans Egede could be a special governor for Denmark, just like how the Ottomans have their own special governor in Civ 6. Hans Egede would give bonuses to the spread of religion in cities built on tundra / arctic tiles, and he should also give bonuses to any and all internal trade routes to said cities.
Something relating to the Sound Toll would be very appropriate as the country ability, no matter the leader or the era - be it a medieval or a 17th / 18th century Denmark.
I should probably re-iterate that I certainly don't mind seeing a medieval Denmark, but I at the very least think that a 17th or 18th - or even 19th century (a cultural civ under Frederik VI or a diplomacy-focused civ under Christian IX would be great) - Denmark also ought to be considered. Valdemar II, Margrethe I, and Christian IV would all be obvious choices for the leadership.