To replace Titius-Bode, I'm thinking of using a log scale to determine approx orbit. Actual orbit can be up to 25% plus/minus.
|orbit|AU|Sol system equivalent
The math shows that it would be just as wrong as the titus bode "law" for the derived orbits of the 4+ world systems already discovered, and for the jovian and saturnian systems of moons.
Titus-bode is essentially a base 2 log with an offset.
Problem is, no pattern to orbital systems has evolved that stands up to the observed measures of the last 7-8 years. And, as yet, we don't have complete enough data to generate a new relationship, but do have enough to render titus-bode bogus and other log scales dubious.
If you're going to go with a fixed scale, Titus Bode is as good as any, because at least you get the Sol System correct to ±0.1 AU through Neptune, provided you ignore anything under 500 mi diameter... and a few larger ones with moons of their own, Like Pluto, Eris, Sedna and Haumea.