There all the same cost yet Hecarim has 3 new particles (I think his W even has a new animation but dont hold me to it). Nasus however has 0 new particles or animations. I get its 750 but it'd be nice if even the symbol his E created was changed.
its mostly because these skins are 750-skins,while these usually don't get new ability effects the other 3 worldbreaker skins are simply exceptions for the following reasons: Trundle gets a new pillar,because new models for 750-skins aren't uncommon(even ability-related models),look at Bard bards new meeps for example
Nautilus gets a new W,because the old one would be extremely unfitting(they did the same with warden nautilus) and obviously he throws his new anchor,because that is part of his new model
Hecarim has his new spectral riders,because his base model looks different,so it wouldn't make sense for him to get his old spectral riders. Though he also seems to have gotten a recolored W(what bugs me is that when his halberd glows from his Q,you can clearly see that it is the old effect,but I guess this might get changed),which seems unneeded and more like a small bonus.
So they all got either model-related ability-updates(Nauts Q,trundles pillar,Hecas riders) or changes to abilites that clashed too hard with the skin itself(Nauts shield). Not sure about why they changed Hecarims W,though it is likely to match his new color scheme a bit more(so it would be in the same category as Nauts W)
In the case of Nasus however he doesn't really have any of these problems,his skills fit in terms of color(actually more than they fit his regular ingame model) nad he doesn't have new models in his kit.
