1A) Allow them to be built a little earlier. The timing at which they come in to the game feels somewhat off. Not only would this make them more useful in practice, but it is strange that the same technology that unlocks them (Engineering) also unlocks the same siege unit that historically contributed to obsoleting Castles (Trebuchets) Similarly, in game, Castles do not become available until they are already on their way to becoming obsolete. As for what specific technology they should become available with: just throwing a couple possibilities out there, I would suggest either Construction or Machinery.
I think Engineering is fine. Construction and Machinery are already hi-prio techs and are far too early.
2A) Have them obsolete later in the technology tree. One of the reasons that Economics is too early other than simply it's placement on the technology tree is that it also unlocks Free Market. For many players, this is too important of a technology to postpone getting for long, if they do not beeline it all together. Thus, not only is this technology too early in the tree to be obsoleting Castle, but it is also most likely one of the first technologies a player will research upon reaching that point in the tree. Thus, again, as for a couple possibilities I am just throwing up in the air to start discussion for new technologies to obsolete Castle, I would suggest Steel or maybe Rifling.
They should atleast obsolete at a appropriate tech. What has Economics got to do with castles? I say... Steel or gunpowder.
3A) Increase the bonuses offered by Castle. This one is the most difficult to offer good suggestions for, but I will try to suggest some ideas that would not only make the Castle in-game more useful, but also make sense historically. Thus, here are some suggestions listed here for easier viewing: (again, if you reply, please say if you particularly like or dislike any specific suggestions)
a) Increase the Culture generated by Castle. As an important symbol of the Medieval Period, I think it would be justified to have the Culture generated by Castle increased to reflect this. And perhaps, after the Castle is "obsolete", it could lose it's usual bonuses however gain a slight increase in Cultural generation? This would reflect the massive "cultural" value and drawing power that the remaining castles of the world still have today.
I don't think the castle should be a
-heavy building. One is fine.
b) Offer a synergy with Hereditary Rule. In the Civilopedia's words, "Castles served as administrative and judicial centers and as a seat of a lord's power." Thus, I think it would make sense to have castles offer some kind of citizen-management type of power, possibly in combination with Hereditary Rule. This could include such bonuses as a discount in city or civic maintenence (for that specific city), less war weariness, etc.
Sounds good... Maybe some kind of mini-courthouse effect?
EDITED IN:
c) Offer a synergy with Serfdom. (credit for the idea to DrewBledsoe) This would both improve Castle's usefulness, but also make Serfdom more competitive with Slavery.
Not that Slavery can't compete with Serfdom in my opinion, atleast with the random event. I usually delay slavery or even skip it now. Serfdom also has a nice low cost. Anyway, good idea.
4A) Increase the amount of Castle costs. Wait - what? Yes, you heard me right, but I have not gone insane, I am well aware that this would be "nerfing" Castles. However consider this: I did not say we should only "buff" Castles, I said we should
rebalance them. This means that all of these suggestions should be taken all at once, which in turn means that if we really are going to make Castle significantly more useful, then it should cost significantly more
to build. We want Castles to be useful, not overpowered. Obviously, if none of the other changes are ever implemented, then I would not be saying we should increase the cost of Castles as they are in the game right now (3.13).
Good reasoning for a complete logical argument, sounds fair to me.
With some ideas on how to improve Castles out there, I will move on to the next part of my overall suggestion.
Part 2) Forts.
1B) Provide a synergy with the Protective trait. Yes, this is my weakest suggestion. The civilopedia lists Forts as acting as a city for combat purposes, but I have never heard if people could use the promotion "City Garrison" while defending on a Fort. If this bonus does NOT extend, then it should.
2B) Provide a healing bonus to units inside a Fort. I hate to list another suggestion that may already apply to the game, however again.
3B) Give units in forts the ability to take "pot shots" at enemy units passing by. Pretty sure I remember this from Civ3, and I see no reason why this should not still be in the game.
4B) Provide defense versus aerial or naval bombardment, and the collateral damage of siege units. Pretty self explanitory.
5B) Allow Forts to be built on Neutral areas of the map. This could obviously significantly improve the strategic usefulness of Forts, though hopefully not make them overpowered. If you actually got to build one outside the borders of a civilization you were at war with, it would serve as a forward-base of operations and a place for your injured troops to regenerate at.
1, 2 and 5 are already implemented.
3 is not really necessary, have a CG longbow in the fort and then some cavalry and you have a Zone of Control. Same with ships.
4 should definately be applied. Forts should also be harder to destroy with bombardment than, per example, cottages.
My own suggestion to a Castle:
Castle, +1
, +25%
, +1 Trade Route, 120
Double production speed with Stone.
Double production with the Protective Trait.
+50% city defense (against non-gunpowder units).
+25% resistance against bombardment (against non-gunpowder units).
+2 experience to units trained in the city if running the "Vassalage" civic.
+1
from farms if running the "serfdom" civic.
Obsoletes with Gunpowder(Except for the city defence).
Eventually, to not overpower Vassalage, the +2 exp could be class-specific (either siege or archers, is my guess).
Whatcha think?