Defaulting to any one instance would be against the goals of federation, I think. Much better to have a centralized site to help people find an instance that uses factors that wouldn’t bias too much. Perhaps pushing towards “general purpose” instances that would make geographical sense. And then you could highlight instances that cater towards more specific groups. But I think the goal of this would be to spread users across many instances rather than funnel them all towards one.
I might propose having something things like server ping be a factor, and capacity of the instance. Perhaps instances could also be shown with their largest communities so that people could see the vibe of the instance before they join.
Defaulting to any one instance would be against the goals of federation, I think. Much better to have a centralized site to help people find an instance that uses factors that wouldn’t bias too much. Perhaps pushing towards “general purpose” instances that would make geographical sense. And then you could highlight instances that cater towards more specific groups. But I think the goal of this would be to spread users across many instances rather than funnel them all towards one.
I might propose having something things like server ping be a factor, and capacity of the instance. Perhaps instances could also be shown with their largest communities so that people could see the vibe of the instance before they join.