Problem is that not every community is the same. Nor is every mod.
You start telling to use activity as your metric, you run into trouble because there's a ton of small communities where the mod listed is an alt account to keep moderation and personal use separate to avoid the bullshit.
Back on reddit, I learned real damn fast to not moderate active subs on my main account. Lemmy isn't much different. Mods catch hell, no matter how good they are. Using dedicated moderation accounts to avoid the bullshit, while observing the community from a main account. If the community never needs action, the mod account looks inactive.
For real people, never moderate a big community from your regular account, even on lemmy.
But other than that, it's a solid idea!