The streamlining of the experience has in general improved the Civ 4 BTS experience, while retaining some of the better features from that. A few things I do miss is the larger game, instead of you and 4 other civ's and a small map, however this is not quite as detrimental to the game as it might first appear if you play on the normal difficulty. It IS still a civ game, and therefore combat results may require a couple save/loads before reality sets in, like a cruiser at 1/3rd your strength sinking a battleship, but overall I find the AI to be enjoyable in how it functions and survives in the game world, the difficulty levels balanced so as to provide a better experience, and would recommend at least renting it.
One instance I played, it was me as China, France, Germany, Zulu, and the Japanese. France strove for a cultural domination victory, and thus were not prepared to put up a fight quite like others. Thus once they started pushing into my territory over a couple wars and several centuries I destroyed them. The next faction to cause problems for my growing China, which is a balanced civilization able to go for all victories, was Germany. By destroying France I had a large region all to myself, as there was just a narrow choke point to the other side of the continent where the other three civ's were. Anyhow, the German's were focused on a domination victory, and produced towards that. Because they were so far away, me and a friend had time to tech up and were able to out do the germans in defense, until the Zulu built a city at the choke point. This put a halt to them causing problems for us, and allowed us to pursue a technology victory by reaching Alpha Centauri.
I'm not entirely sure what the Zulu's domination goal was, as they strove neither towards technical victory, cultural domination, economic success, and while they came to become the island nation of the game, with having something like 5 out of 9 islands occupied by them, they were still not achieving much. Eventually our peace with them ended, and we took their choke hold city, and eventually they conceded peace. However, the Germans had used this time as well to push towards creating a powerful army. If not for catapults, the first deep water navy (which is thankfully now important to have, the naval aspect of the game really makes the late game fun for me, unlike in Civ 4 where the late game was meh and the naval aspect was pathetic), and that defensive city, we would have been surely overrun. Defense, tech, and we strove for pursuit of technology, which allowed us to maintain our existence throughout the Sino-German war which lasted for a millennium, starting around 1000 ad and signing a peace accord in 2000 precisely. There would be intermittent wars with the Zulu, however because of... whatever they were doing, they never really came to bother us until they got a deep water navy and started doing naval assaults on our cities. Eventually we got Cruisers and sunk their galleons, preventing them from ever being more than a nuisance again.
All while this was going on, the Japanese were also rushing towards a technology victory, always several techs ahead of us. When we got fighters, they had started building up bomber squadrons ready to end our existence if we ever thought to challenge their tech victory. In the year 2000, we had beaten them to The Nuclear Bomb, only one in game, and in 2002, it was launched on their second largest city (since you can't obliterate capitals into a smoking black hole). Strangely, this did NOT lead to war. But whatever. After this anti-climatic launch, and 11 hours of defending China, I went to home to bed, and my friend finished the game off later. Not sure how it concluded. Overall, while it may not look quite like it's fun, I would definitely recommend renting it. Nobody reserved a copy, including my friend, I presume no one expected it to do well. But at least considering how many shops and how long we had to wait to find a copy in stores, the entire Puget sound area from Seattle to Bellingham was sold out the first couple days. It may be Civ-Lite, but I personally don't consider that a detriment to the game. It's reduction in scope, while admittedly I do regret, is more than made up for by the re-evaluation of all aspects of the series and the general improvements in function.