It's only the idea - I don't have any fancy ways/suggestions to make this happen however potentially this wonderful community does!
The system we have is definitely flawed in the lower-level regions of the game; I can take this GW as a brute example of this.
In the four guilds fighting in our war, us and two others were primarily level 30 accounts where as the fourth guild was somehow primarily level 45 accounts (already flawed heavily)
One thing which stuck out like a sore thumb was that they had a level 10 account in their guild, 65+ days inactive - I feel like this has something to do with their placement in our war.
On top of this - every time I mention guild war matchmaking to the Veteran players - I typically get a response belating to how the system is broken and needs a rework - hopefully this suggestion comes across well and someone starts working on a few tweaks (or a new system entirely) for the next guild war! 😊