My stance on buying used are, I prefer to buy new bodies but used glass. Bodies tend to have more moving parts and more suspect to damage and repair (though I've yet to have to send a body in for repair, knock on wood).
The Fuji resale value is hurt by two things in my opinion. It's a relatively niche market compared to Canikon and the constant sales and promotions tend to keep people waiting to buy new on sale, then used. Only real way to combat #2 is to buy when it's either used or on sale yourself. Or do what I did when I shot Fuji, buy used while it's on sale. Got great glass from B&H used department during the sale, then when I ended up selling the gear, the sales had ended and prices jumped back up, so I actually made a few bucks selling the 14 and 35.