I reiterate its not about how powerful 170HP would make it but the fact that its so far out of the boundaries of an Espeon's usual HP.
For example, some ascending HP EXs:
Magcargo 80HP, Magcargo ex 100HP
Deoxys 70HP, Deoxys ex 90-110HP
Crobat 90HP, Crobat ex 130HP
Blaziken 100-110HP, Blaziken ex 150HP
Charizard 120HP, Charizard ex 160HP
Then....
Espeon 80HP, Espeon ex......... 170HP?
And besides I think that is not a 7 in the TCG font, compare it to the Feraligatr ex pic below on the official site. Make 'em the same size, tilt them make them the same resolution and you'll see the one on the Feraligatr bends back sooooooo much more.
It even looks a bit like a 2 if you look carefully......