I have no idea what you're talking about. If you don't want to read their reviews, maybe I could persuede you.
BF2:SF is an EXPANSION. It's not here to completely change the game in any way. If you're looking for the game to be changed radically, you should stop reading now. If you love infantry combat, infantry maps, and anything involving infantry, then SF is for you.
SF adds a few new features that change gameplay slightly. Night maps, Ziplines, and Grappling hooks. There are some maps that have them disabled, so if you dislike ziplines, nightmaps, the colour pink, or whatever, you will still have a favorite map.
If you have an extra 30$, go for it. If you have 40$ and you need to feed your family and buy a new pair of shoes, wait some time.
Personally, I love the game. I think it's a perfectly balanced, amazingly fun, different type of FPS which doesn't follow the straight bland, overdone gameplay of CS. Instead, it focuses on fast paced action, teamplay, and most importantly, fun.
Hope this helps.