I own a 2013 Leaf and I really like it, but It's not suitable as the only means of transport for me and I think probably most people.
As a second vehicle for short range commuting it's perfect, for anything else it's a compromise at best.
After owning it as my sole vehicle for a couple of months I ended up buying a cheap petrol car as a second vehicle for those times the Leaf can't do the job.
Over a typical year I will do 5-6 thousand km in the leaf and 1-2 thousand km in the corolla. I use the leaf whenever I can because it's better to drive and cheaper to run. It's likely to take me 5+ years of ownership to break even on the trade in deal I did for the leaf by which time I suspect it's resale value will be virtually nothing.
As much as I like the leaf the truth is when I compare my $17000 2013 leaf with my $8000 2007 corolla the leaf wins on running costs and driving experience and the corolla wins on every other point. (it's actually a corolla Rumion - not too important just a different body style).
One thing you may not expect if you buy a leaf is how often people will feel the need to inform you of all it's short comings, or how often you might end up defending owning an electric car. I think performance ICE car enthusiasts in particular view them as low performance golf carts and not real cars and a lot of people feel like they are being preached at and told they have to own one and react negatively to that. I'm not sure who it is that's forcing anyone to buy electric, but people certainly seem to feel that way.
And on the subject of Leaf batteries. It seems like for the most part they degrade at 2-3% per year in a temperate climate under normal usage. Mine is currently at 35000km and 79-80% SOH (varies). Mileage seems to be less of a factor than age. I think the reality is very few people will spend $5k+ for a new battery when these cars start hitting 12-15 years old and the usable range drops under 50-60 km. $10k+ is just totally unrealistic at that point as well.
So unless some 3rd party starts offer a cheap replacement with improved range I'd say the majority of used nissan leafs are destined to be disposable and only last as long as the original battery. This significantly hurts the environmental impact calculation I think and they may not end up being better than the ICE cars of their era.