I picked it up over the weekend, so far I like it quite a bit. There are certainly gameplay differences, whether or not you would see them as improvements is another story. Since it is based on the Civ V engine, most of the gameplay mechanics are going to be the same. So, if one of the things you don't like about Civ V is the fact that you cannot stack units, unlike in Civ IV, that mechanic is still in place.
You still have to track food and culture, happiness has been replaced with health, and money has been replaced with energy, but there is very little difference between them other than those changes to the names. Religion and tourism have been removed, but since these were added to Civ V with expansions, we may see these come back in some form or another. Trade routes were also added with an expansion, but these are available in the base game for Beyond Earth. The culture system has been tweaked, there are 4 culture 'value' tracks: military, food, science and production. All 4 are available from the start, and although they work much the same way as the culture tracks in Civ V, the interface has been reworked.
As noted, there are no nations in BE, your civilization will be based on a sponsor, which tend to be 'league of nations' kind of groupings. There are not very many of them, so they will get repetitive in multiple play-throughs. I would assume that this will be addressed with frequent DLCs, if Civ V is any guide. Maps are much the same, not very many off the bat, but will likely be more in the future.
Two big changes are how the tech tree has been reworked into a tech web, and the addition of affinities, which are influenced by the techs you research. There are three possible affinities, and leveling up the affinities can determine how you ultimately win the game, as each affinity has a wonder that can be built to win the game once you reach a certain level in that affinity. Of course, you can also win by domination, and there are two other ways to win that are not directly related to the affinities.
Units are a bit different in the way they upgrade. There are far less units, and so far there are no units specialized to your civilization (nor are there specialized civilization buildings). You still gain initial access to the units by researching technologies, but now they upgrade by leveling up your affinities. Each affinity gives you two ways to upgrade a unit when you level your affinity, and most units seem to have 5 upgrades in total. Once you choose an upgrade, all of your existing units of that type are automatically upgraded to the latest version.
Barbarians have been replaced with aliens, but the AI is such that they are not a 1 for 1 replacement. The alien AI is such that they don't seem to attack everyone all the time, especially if you go for the Harmony affinity, but they can be somewhat unpredictable. I found that the alien sea creatures were much more likely to attack my ships, but that may have been because I was initially more hostile to them in an attempt to protect my cargo routes. Later on I discovered that one of the bonuses for leveling up the Harmony affinity is that your trade routes are no longer attacked by aliens.
To sum up, if you are not a fan of Civ V, or think Civ IV was a better game, you are probably going to be underwhelmed by BE. For me having been a huge fan of all the civ games, and logging over 1000 hours on Civ V, I am enjoying BE immensly, but have yet to complete my first play through (should finish tonite). Half of my first day with it (Saturday) was spent downloading the game from Steam, and then upgrading my gfx drivers to get it to play without crashing during the first turn. It is much more stable now, but I have had two crashes since squaring that away. The first was just a crash to desktop, but the second time it actually crashed my entire PC.
