The reducing of water monsters level by one might be considered somewhat op but the 200 boost isn't that great, besides if "this 🔥" is really such a nuisance then why not just put in s/t destruction/negation? Surely it's not that hard...
Twister will stop bugroth dead in it's tracks, as for beatsticks created by alo u deal with them the same way as any other beatstick(eg:mask of the accursed mirror wall the list goes on)
You realize that Legendary Ocean is a card, not a skill, right? The card is bad and is a dead draw in most cases. If you want a Water Deck you're better off just running a pure Hammer Shark deck rather than trying to brick yourself with Bugroth and Legendary Ocean
Eh don't bother explaining it to him,according to his logic cards like molten destruction and the sanctuary in the sky would also be broken lol(they're obviously not and neither is this card)