Eevee shadows system changed in 2.81.
You play with Shadows settings in Render tab, Cascade Size for Sun lamp, Cube Size for Point and Area lamps. New system requires Soft Shadows enabled, therefore you must adjust Sampling settings in the Render tab according to the desired result.
Also for Sun lamp in Lamp/Lights settings tab you play with Cascaded Shadow map values (for example starting the test with a Max Distance value not too high).
Probably the answer is “yes.” EEVEE should first be fast, until your particular situation calls for it to be slower.
In my workflow, for example, I’m not “previsualizing” because I can’t draw. Instead, I’m shooting film, using trapezoid props and cylinder actors, and I want those results now. Later – much later – things like shadows will become important, but not now. And they might never be important for some jobs, like cartoons. So, let the options be there, ready for you to choose to turn them on.
Blender has adaptive detail, so regardless, during animation or camera movement, it’s only ever 1 sample per frame, which is fast. It’s only when there’s no activity that the rest of the samples render out.