Does having a fourth baby help alleviate the middle child issue to some extent?

My husband and I were thinking of having a fourth baby anyway. We currently have three kids(Emily is 5, Lily is 4 and Elizabeth is 15 months) and I sometimes feel like Lily gets overpowered by Emily and Elizabeth. We are financially able to support four children and I'm a stay at home mother so the childcare thing isn't an issue. Does have four kids make being a middle child better or worse?