Cheetah speed will place that much more load on their servers. When addressing server issues, EA had to cripple features to make gameplay possible. From what I can tell, they're brining back these features slowly and likely keeping an eye on server performance. You're right, no coding required to bring this back, likely just an easy token change on their end BUT sometimes code changes are easier to implement than server side performance problems.
Personally though, I find medium speed good enough. It gives me time to plan things out. I rarely have to wait for money to accumulate - if I did, it's generally because I've built beyond my means.