While metric time has some appeal, I think it is not ambitious enough.
Base 10 is not good. 10 just does not have enough factors, so we are left to deal with complex fractions. Let's instead use base-12 numerals and keep time unchanged!
In base 12, 1 year is 10 months (or 265 days), 1 day is 20 hours, 1 hour is 50 minutes and a minute is 50 seconds.
Easy enough!
Edit: wait! I just realized this is still not ambitious enough!!!
What we need is to halve seconds in two. So, in base 12: 1 day = 10 hours, 1 hour = 100 minutes, 1 minute = 100 new seconds.
"Ten", "eleven" and "twelve" can stay the same. "Thirteen" to "nineteen" are more problematic since "*teen" refers to "ten". We would like something meaning twelve-one, twelve-two and so on. Then "two-twelve" intead of "twenty" ? Feels heavy. Maybe stick to "twenty" then ?
If you're going to coexist with decimal, you're best off starting over with a distinct set of words.
For instance, scales have 12 notes, with seven common words for the notes (do, re, me, fa, so, la, ti). Add five more similar but distinct phonemes (go, ki, za, we, je) to insert at the position of the half notes skipped, shift la to position 1 since l looks conveniently like 1, and add nul for zero: nul, la, go, ti, do, ki, re, za, mi, fa, we, so, je.
Add in some rules for forming larger numbers (laj, goj, tij..., soj, jel, jel-la, jel-go..., jes-so, la-gross, la-gross-la, ...) and begin learning your addition tables over again (la plus la is go; go plus go is do; do plus do is mi; mi plus mi is doj).
Personally I think decimal time fails to recognize the cyclical nature of days. Decimal time is like switching from 360 degrees to gradians. A far superior better system would be to adopt radial time and have 2pi hours in a day. We could extend this to the whole year and have 2 pi months in a year, finally divorcing the counting of rotations from the counting of revolutions.
Base 10 is not good. 10 just does not have enough factors, so we are left to deal with complex fractions. Let's instead use base-12 numerals and keep time unchanged!
In base 12, 1 year is 10 months (or 265 days), 1 day is 20 hours, 1 hour is 50 minutes and a minute is 50 seconds.
Easy enough!
Edit: wait! I just realized this is still not ambitious enough!!!
What we need is to halve seconds in two. So, in base 12: 1 day = 10 hours, 1 hour = 100 minutes, 1 minute = 100 new seconds.