There are definitely some game design elements I don't like, and wish they'd have done more like the original. I can sort of see the reasons for it; some I like, some I don't.
OG Multiple bases vs EU single base - Many OG bases were simply radar/interceptor bases, with maybe the odd storage depot. EU has satellites/interceptors, and no storage limit. Mostly a good change - you're not size-limited on living quarters, workshops & labs. As in, OG labs/shops/quarters held limited workers; EU labs/shops give bonuses, but you don't need them to research or build.
Abduction missions - don't like it. OG, the only missions (other than terror) were if you shot down a UFO (or watched it land) and sent a squad. You needed to expand your radar coverage to do this, and failing to would increase panic from all of those unseen missions. EU, it feels like you have to wait for an abduction mission popup and then abandon part of the world. I do like the different reward choices, but would rather have had one abduction mission, with a choice of rewards from the country - cash, soldier or eng/sci (based on what the country gives monthly).
UFOs - OG, one of my early tactics against large UFOs was to wait for them to land, and then send in the troops - because I couldn't shoot them down yet. I'm not sure if you can do that in this one, as I've been sending interceptors out (Firestorm w/ EMP Cannon, woo!) all the time. Although you do occasionally get a mission to one that is already landed.
Squad size - mostly liking this one. 4 starts rough, and you really need to make the Officer Warfare School a priority, and then the squad size improvements. Once you get those, you can start mixing in a rookie with your more elite troops (if they're alive), so that you can build up more elites. Plus I'd say they did it to help cut the mission time down some.
Also, there's something hinky with the RNG. One of my earlier missions, I save-scummed hard at the end to test it, over 10 times. Here's the setup, and order of my attacks.
1 Muton at 5 health, trying for a live capture.
1 Heavy, 23% hit chance on the Muton (and Holo Targetting, +10 aim for everyone else)
1 Support, 30% hit chance (pistol) on the Muton
1 Assualt, 49% stun on Muton at 5 Health.
Every single time - miss/miss/fail. Reload, same, for over 10 reloads. That's a bit improbable.