Yeah but we need to put this into maths to assess.
It is also worth noting that Illuvials do benefit more from offensive stats in a different way than defensive stats. For example Ryplance Omega does % max health damage based on its Omega Power. The game is balanced around all Illuvials starting with 0 Omega Power, but this setup breaks that a bit.
HP - 50%
RES - 25%
OMEGA - 50%
AD - 50%
AS - 25%
HP - 1000
RES - 100
OMEGA - 100
AD - 100
AS - 1/s
Baseline (Tatopee Omega)
Effective HP = 2000
Effective DPS = 100
Effective Omega Dmg = 750
TTK w/o Omega = 20s
TTK w Omega = 12.5s
Perfect Illuvials (Tatopee Omega)
Effective HP = 3375
Effective DPS = 187.5
Effective Omega Dmg = 1125
TTK w/o Omega = 18s
TTK w Omega = 12s
Perfect Illuvials (Tatopee Omega) (RES is 50% Instead)
Effective HP = 3750
Effective DPS = 187.5
Effective Omega Dmg = 1125
TTK w/o Omega = 20s
TTK w Omega = 14s
Perfect Illuvials (Tatopee Omega) (1 Fragment Each / Fury/Defiance (10% AD vs 100HP))
Effective HP = 3600
Effective DPS = 206.25
Effective Omega Dmg = 1125
TTK w/o Omega = 17.5s
TTK w Omega = 12s
in Summary here is what I think is happening
Firstly, resistances only increase by 25% from stats, and are not influenced by levels, this does create an uneven playing field from the get-go in favour of damage dealers.
Secondly, many Omegas get outsized gains from a boost in a way that resistance and HP boosts do not, with the exception of items that grant % Max Health boost.
However the largest component here is actually the types of component buffs in the game. Take DPS for example. Attack speed buffs are +20% or +15%, same with damage buffs, this calculates directly on top of stat boosts since they are baked into the Illuvial, this creates a compounding effect. Items on the other side don't do this. They are +100HP or +20 Resistances, which doesn't benefit from stats at all.
Therefore DPS Illuvials benefit more in 3-4 different ways, which will shorten games.