im not sure if you have the same feeling but its so annoying that almost every time you pick your character its the one that isnt that useful for the next map. for instance not having picked your operative when you have a hack objective. not having soldier when you need to blow the bridge.
i know they talk about the ranking but IMO that is just massively impacting on gameplay. if i make a new level 1 character its still me using him and i will come top of the xp board. i think this limitation it having a negative affect.