Yeah - that's my lineup, Arb + Maulie + Lydia + Rotos. This specific matchup, though, was versus a team running Arb + Lydia + Big'Un + Astralon. Now, of course this is arguably the worst matchup I could face for Maulie, since Big'Un smacks her hard. That being said, both of the times I lost, my "normal" strategy worked - Maulie and Arbiter got wiped out by Big'Un, but Rotos passive kicked in to save him, and gave him an extra turn. He proceeded to delete Big'Un, but then the reaction passive on Astra triggered to save him from death.
If I were running ATK% gloves instead, I expect even the non-critical hit would have been enough. Just trying to think about whether the future is going to look more and more like that - especially for matchups against go-second teams.
A common matchup for me is to take my above team against those running, for example, Duchess + Lydia + Vogoth + Ursaga. Usually I have no problems winning - standard rotation, and then Rotos deletes Ursaga and Vogoth on his first turn, and then eventually finishes Duchess off. But if that Vogoth and Ursaga were both in 3-piece reaction sets, I could easily see my first attack on Ursaga just doing nothing at all.