Maybe I can use this thread for sharing some experiences. I haven't actually finished the mod, but have gotten moon flight, plasma, etc., and every mission is essentially either easy or very easy, so I'm getting a bit bored of the game and I wonder if I have the energy to finish the mod. Rather I'm more tempted to start over or try another mod for a while.
I haven't really played UFO that much, I'm much more a TFTD guy. Never played other UFO mods except hardmode expansion (up to halfway point). But I loved TFTD TWOTS mod, which I think was for me ideal for the depth an campaign length perspective; XCF seems like a little too long for me.
Exactly the opposite to OP, I liked the early and midgame best. It is a striking difference to "regular" UFO game and as such interesting, when you have to develop everything slowly and do missions deliberately (especially if playing ironman), instead of getting almost everything immediately. The slow ramp-up of X-Com facilities, enemies, challenges makes the first year or two very interesting.
The cult HQ/manor phase seemed to be the most difficult part of the game (when there are 50, 100 or even more enemies, sniper/spotter logics in outdoors, indoors in cramped corridors, not too many agents, more or less lousy weapons, not very effective armors, etc., tricky avatars to capture). However you could get by even in ironman with proper, usually cheesy tactics such as throwing huge amount of grenades, camping, etc. The bad thing is that the enemy AI seriously discourages you from using grenade or rocket launchers, mortars, etc. In contrast, for example, alien and hybrid embassies, even large ones, were exceptionally easy at the point that they appear; usually the mission is over in 5 or 10 turns (maybe my contrast is TFTD alien bases which are a complete nightmare and I never do them without psiVision/MC unless I absolutely have to). Especially the MIB, hybrid, and similar very refreshing and "something different". Also, the underwater plotline, when you get to the undersea city, was very profitable: you could get multiple power suits from the gillman hero by repeating the mission over and over again, and sell off all the aqua plastics you otherwise have no use for: very easy to get rid of mid-game money problems. Upon restart I would likely to try to rush into that part of the game.
The game started getting significantly easier when I obtained the first transformation (in 3.0-snap), the spartanism. With 100+ TU with huge stamina and other bonus stats, especially fixed TU battlescape actions would make them by far the the best there is for certain roles (superb, for example, for running around especially indoors and killing/stunning enemies with melee weapons). Also, they are ideal for carrying power suit, because its TU reduction does not hamper them at all compared to other soldier types. If you compare spartans to kyberos, you already get sufficiently high accuracy and other stats with the bonuses, but you get way more TUs and stamina, which increases the ability to move around quickly (or, for example, heal a hit of 7-8 fatal wounds in one turn with one agent).
What I found daunting and frustrating at times was the huge arsenal of different kinds of human weapons, where even half a dozen of them would do essentially the same thing as the next one, with very minor differences. It took quite a while to figure out which ones would be useful, and the vast majority would be essentially duplicates of a few major ones or trash (of course, many of them could be used in an emergency, but who cares to micromanage each weapon, required clips, soldier equipping, etc. for each of them?). And researching all of them is just a waste of time but obviously a thing for completionists. But it seems this is intentional and I suppose this adds to the realism aspect (different weapons filling the same niche employed in different parts of the world) and I don't think it's going to change but rather is likely to get worse for the first-timer perspective.
Except in the earlish game (with slow transports), I didn't really see a need for multiple strike bases, rather operating with Kitsune from just one, leading to quite a bit of simplicity and less micromanagement with agents, equipment and such. (And prior to kitsune, skyranger or prior to that osprey that could also first fly-transfer to another base -- all fast enough to outrun cult vehicles if stumbling upon early manors.) You could just shoot down most of the subs and if the aliens build a base, it's only a very quick mission to kill it (after you get bored with farming the supply ships).
Also the huge variety of various damage types and resistances (+ various armor ignoring properties) at least in principle seems to allow for variability in the game and this could be something one could try to explore in other campaigns. I didn't even really try to figure out if trying to leverage for example WARP or CHEM or similar weapons obtainable from technomads, hybrids, etc. earlier in the game would have made sense (it didn't seem sensible to spend so much researching them early on, as there were more pressing alternative).
I didn't even bother with alien laser weapons because they didn't seem very interesting, but rather sticked to BO auto-snipers and several other rather boring weapons (such as MAGMA rifle with chem clips) until I got turbolasers. I wonder if alien lasers are even really that useful. The maxed soldiers with sniper shots, ignoring some of the armor, (even without alloy ammo) are lethal against almost everything. I tried tactical sniper rifles, but found that the lack of reaction-firing snap shots, limited moveability and only a little improvement over BO auto-sniper didn't really call for using them all that much.
In early-mid game, the alien alloys and elerium is very scarce and you want to conserve every bit of it (for example for thunderstorms, armor manufacturing and improved/advanced lab, I didn't even dare to use it for almost any tritatanium ammo), but soon after bigger alien ships starts appearing it will be abundant. An interesting balance at least for the early game, though I doubt a bit who will bother and can use the precious alien alloys for tritanium clips or most of the other weapons goods - and when you have abundant supply of the components, you no longer really need it.
There appear to a be a very small chance of getting alenium shards, so getting new ones is very heavily based on RNG (I don't think I got any new ones in the game), which could be an issue if your AI unit gets completely destroyed in a battle. I wonder if they should be a bit more frequent in case you get screwed.
I would suggest lowering the cost of researching MIB agents. They appear early, but compared to other early game topics, they seemed so expensive I skipped them completely for a year or two. I suppose it shouldn't be so discouraging to research them, given that quite a bit of research is required to obtain game progression (MIB activities). Compare, for example, to various alien hybrids and the network/operations topics you get from there.
It would be nice if the OXCE engine allowed to you to select which transformations/boosting you want to hide from the transformations overview screen. But as you can't, you should be better off not even researching the ones you will never want, to not bother you on the screen (that will go on for multiple screens when you have everything in any case).
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By the way, I mentioned Starving Poet's reverse stat strings submod earlier in the thread. For anyone interested, I made some updates to it (added new transformations, decreased the threshold - in the original after obtaining 90% of the stat cap it would no longer report as trainable, I increased it to stat cap minus one), if anyone is interested. Highly recommended, I suppose I'll copy the idea for some other mods as well.
