Yes, many older DOS games (depends on what type of games you are targeting) where quite speed sensitive, even on a 486DX2 66 MHz.
Hence, why many of those PC's had a turbo button that allowed you to slow down the speed of the CPU (provided it was actually connected to the header on the motherboard).

Unfortunately, the faster the CPU's got, the less effective the turbo switch was (if even at all).
However, there are other methods available that will allow you to slow down the speed of a "faster" CPU (for example, disable the L1 or L2 cache in the BIOS or via a utility).

I think most games were no longer speed sensitive by the time DX2 66 became main stream.
Their will always be the a few exceptions but if it runs on a DX2 66 it'll probably run on anything newer.
(The Pascal Runtime Error 200 being a big one that only hits round 200Mhz)

But as jesolo said the DX2 66 (and faster CPU's) are already too fast for a lot of earlier games.

Was the AM586-133 P75 too fast for some 486-era games?

Yes is the short answer. The 5x86-133 is just a fun one to play with. It's an awesomme CPU, and it's perfect for 94 to 96 gaming.
Just not for games earlier or later than that. Basically speaking, it fits a 2 year windows.

DX4-100 is what I run now, and if you disable caches and throw a turbo on, it will probably go as slow as an 8088/8086.

With a board with the right implementation of turbo functionality, I believe the Am5x86 hits a spot where you go from 133 MHz to 33 MHz equivalent by toggling turbo and 386DX grades by disabling caches.
My long time ongoing project is a machine that could switch from a low Pentium class performance to Ultima VII and on down to Wing Commander.