Yeah I know... really lame huh?
Despite the fact it doesn't have much detail to it, you have to remember that Eevee doesn't gain much detail to it. Yup, this is the Normal evolved form of Eevee.
It doesn't evolve from location, stones, or friendship. Exeon actually evolves from Eevee at LV 35, but people rarely have it evolve to its next level like that because they either use a stone, location, or they save it so the friendship will cause it to level into the others, thus: Exeon is rarely even seen.
I created Exeon what I was about... 10. I figured that Eevee just needed a regular Normal-type evolution and got Exeon... and since it's just a normal evolved version of Eevee, I didn't figure Exeon would have a whole bunch of detail and would just look like a normal Eevee with it's fur extended and grown more and to where the Eevee's tail eventually splits into two parts