I know several people have said that a 68000 is too slow to run WHDLoad, and I agree with that.
In the majority of cases WHDload will run fine with 68000. Some of the "fixes" done for 68020+ CPU's can be detrimental on games which relied on exact timing. (e.g. Turrican 3 intro)
9/10 times where people have reported WHDload being too slow on their 68000 Amiga it will be because they don't have enough memory to pre-load the game image + kickstart emulation into RAM. In that situation WHDload will attempt to load the game dynamically from disk. Each disk access requires stopping the game. Accessing the hard drive. Starting the game. Very slow.
So you need between 2 and 4Mbytes of Fast RAM + 1Mbyte of Chip RAM to be able to run most single disk games.
is it possible to run it with a 68010?
Yes and adding a 68010 CPU will give WHDload the ability to quit back to the OS without a reset. But RAM is key... not CPU power.