whereas the Devores are built with wood blocks to couple the enclosure to the floor?
Yes its likely that Devore accounted for the effects of their chosen coupling method in the sound profile of the speaker - much like some designers account for the effect of a grille in the voicing. Decoupling may then result in undesirable effects like you found.
Shows that you can't make blanket assumptions when there are so many different design (and room) variables in the mix. In any case it looks like you've given the decoupling methodology a fair hearing.
Given all the positive feedback for the Gaia footers I was perplexed when I didn't get a positive improvement after installing them. The ATC plinths have threaded inserts and I was careful to align the logos of the Gaia per the instructions - the speaker positions were marked and duplicated after install.
I have my suspicions as to why - the already mentioned height difference was one. The other was the bass traps I had in the front corners of the room at the time. These had a positive effect with previous speakers - but I subsequently found that the bass traps were robbing the big ATCs of some bass heft (the SCM100s have a taut, neutral bass alignment but go fairly low in room). The effect of the bass traps and the slight balance change of the decoupling (less room interaction) probably contributed to my negative impression. Not sure where the Herbies came in the subsequent timeline but the Podiums were installed after the bass traps were removed.