The biggest change in regard to formulas in general that the 4.0.1 patch introduced is the change in how the Global Cooldown (GCD) or the cast time of an ability interacts with latency because of the spell queuing mechanic changes. This results in a simpler form of calculating the Damage per Execution Time (DPET) of abilties bound by the GCD since the latency factor is effectively removed unless latency exceeds a large amount (500ms+).
Naturally there are a lot of specific changes which occured to abilities and stats in the game affect math related to them particularlly, but at a higher level of core concepts, the spell queuing mechanic change is the only one which has an impact on all formulas across the board where latency was and still is a factor.
This is the only 4.0.1 change I can think of with a universal impact.
"In anything, if you want to go from just a beginner to a pro, you need a montage." /w TankSpot WTB Montage for Raiders.