This is actually not that good because it allows your opponent to reuse Leles and gives them even better draw rates for their own supporters because of that. Everyone knows how valuable the late game Lele for Guzma for game is. Not really sure you want to increase your opponent's odds of doing that. 1 active Pokemon and 2 bench is still enough to close out games. 2 Gardevoirs and a Sylveon. 1 Turtonator and 2 Volcanion EXs. This just doesn't disrupt nearly as hard as Plea GX since your opponent picks what stays and what goes. Cyrus also prevents your opponent from decking out which is cute.
Plus, your active must be Metal or Water, so if someone Guzma's a utility Pokemon like a Lele or Zoroark GX or Oranguru into your active and you can't get it out, then you can't play him. Not to mention Solgaleo decks can't even use this until you actually reach stage 2. It's a dead card prior to having Solgaleo in play. You'd mostly rely on Registeel or Solgaleo Prism Star in your active to pull off Cyrus early.
The more Leles your opponent has on bench, the worse this card is. I more or less see Cyrus right now as the "replacement" to Parallel City in standard format after next rotation, just like how Lusamine "replaced" VS Seeker's basic functionality.
I think this card needs more context, as in I think he'll make more sense as part of an entire strategy that's coming out in SM5. We could have Dialga and Palkia cards with abilities or attacks to reinforce this, i.e. "if your opponent has 2 or less Pokemon on the bench, this attack does X more damage."
First impression: Wouldn't bother putting this in a Solgaleo GX deck at all.