I had a 68010 in my A1000 before I bought my A1200. Then i put the 68000 back.
The 68010 did give a small speed increase that was sometimes noticeable, but there was software that wouldn't run with that CPU. There was a patch on a Fish Disk (should be on Aminet now) that trapped the problematic MOVE SR,EA instruction (going totally from memory). Actually, I think there was more than one. I remember "DeciGEL" and maybe "SuperDeciGEL" and maybe somthing else.
That patches didn't work with games on custom boot disks, of course. IIRC, Shadow of the Beast was one of the games that wouldn't run with the 68010.