Afaik, that's sumerian time, not Imperial time. They used the thumb with the finger phalanges, giving 3 * 4=12 options. Together with 5 fingers on the other hand, they got 12 and 60 as bases. I don't know why they just didn't do 12 * 12. The 24 should be looked at as 12 am and 12 pm, the day starting at noon, so it's more like minus 12 to plus 12.

But as we're engineers, lets do a back of the envelope trial:

You're mostly stuck with days, months and years because of astronomical facts.

Seconds are close to heartbeats which has some psychological nicities: People used to count short times in heartbeats. You might be able to redefine a second as 10 millidays.

Weeks tend give decent divisions between work and free days. I remember reading about the USSR messing with the week rythm to get more work time, and it severely backfired in productivity. So you'd need to find a way to give about 8 days in each month as new weekend. Numbers 30 and 8 are hard to decimalize. Maybe define a week as 10 days, with day 1 of the week a holy day, and 1 or 2 more day in the week that workers can choose themselves. I don't see weeks getting much better like that.

The french did give it a try in their revolution, but I don't know why only that part of metrification failed.