A science-centric game (citizen=science) brings the completeness of the tech tree more in play.
1UPT is far, far superior to SoD, particularly from the standpoint that it is much more fun to play. People way overestimated AI's ability with SoD (I witnessed so many suicide stack attacks that it was stupid), and underestimated AI's 1UPT ability - ever face an early Japanese rush on multiple targets? Plus, many of us are old wargamers and trying to figure out how to move units on a hex-based map was one of the greatest gaming experiences, esp. in trying to deal with terrain, line of fire and zone of control. Besides, there was no skill or fun in moving a bulldozer (and RTS-like rushes) but there was much more in trying to fit 7 units into an enemy terrain that only had room for 4 - so which 4 and in what order of battle?
Sure, the AI does not do that as well, they didn't do that well in wargames in either, nor did they do SoD that well. In Civ5, that's what difficulty levels are for.
Having 4 cities where every single resource is a decision-point (which is the basis of playing 4x games, not covering the map with SimCity-like messes), instead of the massive, over-production of Civ4 = less decision-points and less value (in acquiring, trading, losing or fighting) of each resource.
Civ4 was my favorite game until Civ5 came out. While the initial release was problematic, it was playable and I and others had many fun games - more than I had in any Civ4 games. But I anxiously awaited the patches and the expansions to see if they would greatly improve on the new designs - and they did beyond anyone's expectations, particularly in making a culture victory fun to play for first time ever.
I get it, you love Civ4 and can't let it go and you and others spend so much time slamming those of us that love Civ5 that it gets really annoying and tiresome, esp. when you and others hijack Civ6 threads. People like you and Sullla wanted a different game, as long as it was Civ4. In my opinion, Civ5 improved on nearly every aspect of Civ4 (not all, though) in making the game more fun to play and bringing in a much more diverse Civ experience. If you and others can't understand that, then don't bring it up in every thread.