In most duties if you are good with your MP management then Lucid Dreaming is more than enough. Yes occasionally you may feel having a Ewer is necessary, but if you are either over DPSing that you run low on MP or are healing ineffectively (i.e. lots of AOEs, or constant Benefic II etc) then that's a learning issue to be fair. The fact that more MP can be restored by other allies (more accessible Refresh and Mana Shift) is just a bonus, nothing much in terms of AST MP has changed much after Stormblood and the management is still there regardless.