In 4e the advantage of Kevlar was it gave Ballistic armor (aka vs guns) which you couldn't get till Titanium normally. The price for it was the lower Body modifier and the missing damage compared to Aluminium.
In 5e that advantage is gone, since armor is armor now. Kiirnodel's version of Kevlar is just striclty worse than Aluminium, with the exception of nuyen.
Heck, even if you change it to Body 1, Armor 3 (to simulate the "better armor" portion of the original), it would still be worse. Damage resistance is a +4 on both, and Kevlar still has no damage.
Also armor can be reduced with AP, while Body can't. But let's be honest, whoever has bone lacing usually has so much armor elsewhere,that they're not likely reduced to 0 by AP anyway so that's just a theoretical disadvantage.
But that would probably justify the price difference (also remember, Aluminium is 18k in 5e, so 10k is almost half price).
Just my 2 cent.
Ceramic vs Titanium: -1 damage resist, -1 damage, for -0.3 essence and 8k less nuyen (Titanium is 30k in 5e)... that doesn't seem to weird.