While unique tile improvements are one of the best ways to distinguish civs, I think the early, faith focused ones from release were very underpowered compared to the DLC ones.
-Kurgan
-Sphinx
-Mission
The Mission's buff in the summer update highlights that firaxis probably realizes some of these need tuning. Scythia is powerful enough, so i suppose we can let the kurgan be.
Let's look at the Ol' Sphinx:
+1 Culture (+1 Culture with natural history)
+1 Faith
+1 Appeal
+2 faith if next to world wonder.
While the wonder-building theme of Egypt is in here with that adjacency bonus, pretty quick into the game, UIs compete with districts, wonders, and farms/mines. What does the Sphinx offer that those don't? Since improvements cost hammers by way of builder charges, even a religious egypt may prefer to simply invest those in more holy sites.
The stepwell, IMO, is an example of a UI that does everything right:
+1 food (+1 if next to farm,+1 at professional sports)
+1 housing (+1 at sanitation)
+1 faith if next to holy site (+1 faith at feudalism)
Housing is tough to come by early. The stepwell can give you +2 food and +1 housing- basically 2 early farms- right off the bat. That's huge for growth. And equally important, it gets better at that task as you advance. Pay attention to those 3 upgrades it gets from the tech/civics tree. Remember, it will be competing for tiles with lots of other choices! The Mission, if on a different continent and next to a campus, can end up giving +8 (4 faith 4 science.) Now that's pretty competitive with a farm or mine. The outback station really turns into a gem late game too. I don't think many of those upgrades from the civics tree were in the game in october 2016.
What does the sphinx get over time? An extra culture point? This is where the power deficit is: it has limited potential. At best, a world wonder will give 3 Sphinx spots for maximum yield- and with wonder spamming limited by terrain, this hampers Egypt's potential sphinx usage. I don't know how popular faith based improvements are amongst players, but potential buffs could include some kind of benefit for wonders and districts next to sphinxes:
-offering an extra 15% production towards those plopped next to a sphinx.
-Letting the Sphinx act as an adjacency bonus for districts next to it. (at some point, some Civ should get this)
-Wonder Tiles gain culture and faith for each adjacent sphinx, sphinxes gain culture and faith for each adjacent wonder. (Possibly only letting the sphinx be built next to wonders, but next to each other, if we buff it like this)
I think a similar argument extends to some of the city state UIs- they might need a pass through the civics tree to enhance their yields late game, or make them more powerful but more situational. Perhaps the Monastery gets boosts from adjacent luxury resources, etc. They shouldn't be so good that you want to spam them on every tile, but they should be something that make you think "Wow, if i had Suz over that CS, I could really make some powerful UIs right there."
The historical flavor makes egypt so fun to play in every civ game, but I feel like they just don't have quite enough juice in their UA or LUA, which are passable I guess, but the Sphinx really is a let down. It's one of the most recognizable works of Egypt and we get this. Either buff it, or pull a Civ4 & let egypt build a unique monument, the Obelisk, which gives some extra benefits.
