Espeon and flareon could become new great blissey killers, not weak to zenheadbutt or dazzling gleam while sporting some of the highest DPS in partly cloudy weather, with their candy being far easier to get than other blissey killers, or the need to spend the raid pass
Umbreon and vaporeon will have more improved defensive standings, as bother were resisted out by fighting and grass respectively, last resort gives both some teeth against their counters.
However those 4 are the only ones it really helps, jolteon sadly cant deal with ground types even if given last resort because most ground types are part rock. PvP it might have some coverage for all 5, so that is something to consider, but as for what the game currently has to offer, that seems the best uses for them, surprisingly, it did benefit and improve pokemon while not totally outclassing their past selves
