From release, I've liked Egypt and considered them a quite versatile civ. I'd digress that this doesn't necessarily make them a powerful civ. The biggest problem with my perception of them is the power-creep that has occurred with the DLC civs (although I have to admit, the expansion civs seem slightly more tame.) Specifically, Nubia does pretty much everything that Egypt does only better:
-both civs have an early game ranged unit, but Egypt's is prohibitively expensive. It doesn't matter how strong they are (and they are quite strong) if their cost is such that you can almost never build one. Nubia, by comparison, has one that's considerably stronger than its replacement and has extra moves for only slightly more which is negated by one of their other bonuses. The MCU is like an uber strong Protoss unit that's going to be encircled by 8 significantly weaker zerglings and be eliminated quickly.
-both civs have a unique improvement. Egypt's UI is considerably more versatile meaning you have the option of having several of them per city, but they aren't very impactful, even en masse. Nubia's UI is designed so that you probably won't have more than one per city, and they won't be in every city, but the cities that do have them are going to have two significant bonuses applied- first, the district-building bonus is doubled, and second, by selectively placing your districts you can have one strong- to super- class tile.
-both civs have a bonus to building districts, but Nubia's is 20% to Egypt's 15%, it covers all district placement against Egypt's limitation of riverside districts, and in select cities the bonus, which is already better, can be doubled. Egypt's bonus also applies to wonders, but in high-level games you aren't going to be making that many of them, particularly early on giving them more turns to impact the game as a whole.
-both civs have an infrastructure bonus (Egypt's extra gold from external trade routes and incoming trade routes vs. Nubia's mines on resources) but Nubia's is usually more impactful and always more practical. For Egypt, you can't control (though you can influence) where other civs send their routes and whether or not they are to you, and sending your own routes externally comes at a cost of a higher-hammer internal route, which is better for most strategies. For Nubia, though, mined resources are always high priority tiles to work, and hers are a bit better.
Having said all that, I still like Egypt and consider them quite versatile. The one yield that I never have too much of a need for is extra food - at a certain point, it's just bringing you to your housing/amenity cap a few turns sooner, and I'd much rather have a city take an extra couple of turns to grow if some of their other yields (beakers, culture, faith, gold, and most of all hammers) were a bit higher. Keeping that in mind, the sphinx gives you an option to get yields other than extra food from flat grass and plains that other civs without a UI can't do anything other than farm. And even those who do have UI can't do anything to floodplains other than farm them, whereas Egypt has the options of increasing culture and faith with the UI or use these tiles for districts, and the district placement can help with some adjacency bpnuses that other civs wouldn't be able to get. Also, I've said it before, but while Egypt's riverside district/wonder bonus isn't big, it's the most versatile - some civs get bonuses to building wonders, some civs get bonuses to building districts, but only Egypt gets a bonus to both. Furthermore, all of the civs that get bonuses to building wonders only get them for certain eras: China's bonus only applies to ancient and classical era wonders and then it basically expires, and France's bonus doesn't kick in until medieval and expres after industrial. Egypt is the only civ whose wonder-bonus applies to all wonders (provided you place them accordingly) and is the only civ that has a bonus to both wonders and districts. As for their trade route bonus, I pretty much disregard the external TR gold bonus, perhaps you could use this from a Great Zimbabwe city and get a little bonus on top of it (basically as if the Zimbabwe city had two extra bonus resources.) I'm more interested in experimenting with the bonus two gold from incoming trade routes: Presumably (and maybe I'm wrong, I don't know the algorithms that determine where AI civs send their trade routes) the AI probably sends their TR to the destination that gives them the highest total yields. If you can place a city on the end of your empire so that multiple civs can send multiple trade routes to it, and then send both of the great merchants (which the other strategy will lend itself to a high output of great merchants) who give +2 gold for both civs sending a trade route to that city, that means, in addition to Egypt's bonus, the AI would get a bonus of 2 food and 4 gold for each trade route sent to this city, plus the extra from it's districts. This should probably make that city the highest output TR possibility for any TR that can reach it, and Egypt would get +6 gold per trade route sent to it (Egypt's bonus of +2 plus the extra 2 gpt from each of the two great merchants.) This could, theoretically but quite realistically, lead to a bonus of almost 100gpt, perhaps even considerably more late game, and it's a completely passive bonus to be added to all the gpt-producing things that you're actively doing as Egypt.