Summoner utility is really strange. Radiant Aegis isn't always available but it last 30 seconds so you just have to predict when you'll need it early. Phoenix gives a raidwide heal and a single target heal but it's part of a two minute rotation so it's also not always available. Physic is just awful and useless. Meanwhile RDM always has access to Vercure and while they both can revive RDM is notably better at it. Magic Barrier doesn't require you to shift your entire DPS rotation to be useful and can be placed where it's needed because of this. Summoner Utility just isn't up to par and I'm definitely not seeing how Manaward on Black Mage comes remotely close to either class in usefulness.