I used to still play Civ4 Vanilla, because of the superb SevoMod.
In my mind all the additions and MANY civilizations in SevoMod were much better than pretty much anything in Warlords.
Unfortunately, Sevo won't update the Mod for Warlords, understandably because of the enormous amount of work it would take.
Just recently, I tried the ViSaMod 2.10 on Warlords and I was once again blown away! What a great addition!! So many civilizations, many unique units and buildings, restructured tech tree and foremost: a whole new timing and feel to the game.
In both Vanilla and Warlords I always felt that science/building/training were a little 'off' in their timing, maybe too rushed, even in 'Epic' games.
So, yes, with the ViSaMod I 'returned' to playing Warlords, without it, I probably wouldn't.