As a Udyr main I'm inevitably in love with Zz'rot portal. It gives you good splitpushing power and strategy development on the map. Unless it becomes a fucking game breaker myself. I just played against a team with 5 tps, cdr on summoner spells and 5 zzrots. We were winning hard in lane, until they decided to 5tp on 1 lane as soon as they had their 5 zzrots and pushed that lane to base, after raping our botlane. Portals had so much life it took like 3 minutes to clear them all. Then they backed and repeated going 3-1-1 too keep their lanes unpushed but still hard push with portals when they had them available again. They insta won the game.
Being with a full premade myself, we decided to try out the strategy, so as these guys did, picked 4 tanks and 1 adc to have major scaling on our rots. We were loosing so hard in kills and objectives, expecially for a very fed shyvana on their side, and had a 7k gold disadvantage. But still, we won. 5 portals placed with tps are just too hard to clear and minions don't even brak them, so they freeze everything. This works very well with a nasus in team which of cours can create a lot of pressure. I gotta admit we didn't deserve that win, we didn't care much about vision nor objectives, they also had 4 dragons and 2 barons. But the thing is just broken.
I feel like Having too many zzrots placed on the map just break the game, there should be like some kind of limitation, like max 1-2 portals placed on the map by each team. If everybody will adopt this strategy also with more brain as we did, the game will just break. I say it in the interest of the community. And everybody knows how LoL community is, if there's something exploitable or just op, everybody will use it and spread like a virus.