I mentioned in my previous post that the only fursuits that appeal to me are those having an "animal vibe". It's hard to put into words, but I understand my taste and that gives me an idea of the criteria my fursuit would have to fulfill.
It mustn't be completely impractical. I want to have at least a realistic chance to be in a fursuit without killing my back or other body parts after 10 minutes. So things like quad suits would be right out.
The species would be a were creature.
The problem with humans in costumes is that all they can really pull off are humanoid creatures. Trying to mimic anything else will inevitably look off, so I wouldn't even bother.
Fursuit makers have some tricks to adjust the perceived proportions of limbs without negative side effects. I think it's cool, but I would go one step further to really push it from the "anthro" into the "were creature" category: Stilts. I don't have the link anymore, but a few years ago I came across a project site to build stilts which essentially elongate your foot in a way that makes your legs look convincingly digitigrade.
And that's when things would become impractical, and I'm sure it would still start to hurt very quickly. But it's the most realistic solution I could think of to have a fursuit even I would be happy with.
Of course, having one would also require going to events with people because there wouldn't be much of a point otherwise, and that makes it very unlikely to ever happen.