The only Silver+ soldier worth leaving un-CC'd is Phyllis due to the fact she's a UP generator whose skill does not change after CC and being a silver her stat potential isn't huge after CC (the other two UP generating soldiers whose skills don't change are the two plats, Jerome and Zenobia, both viable AW candidates), so it's fine to leave her at a low cost since she's not blocking much beyond the initial rush anyways (you're dropping her, letting her block until skill's up, using it and withdrawing). Some early game strategies actually depend on having an un-CC'd Phyllis (the 3 extra cost means 3 extra seconds before skill use and IIRC Castle Retake is one of the maps where this strat is used for earlier UP gen)