I liked the layer grid for visual queues where the rows/blocks had significance in my projects. In 2.8 each collection must be named (or else chaos incurs). But naming each collection takes time, where layers were much faster.
I like your suggestion and if collections could somehow allow users to treat them more like layer for rapid shifting around of objects then I might be able to keep pace with the 2.7 counterpart.
I am not sure if I am old school, or if old school is the only school, but I would really love to see a timed model design competition pitting Blender 2.7 against Blender 2.8 and see who can make models faster, I am not referring to rendering rates or artistic capability, just simply modeling things…
I am almost willing to bet that 2.79 kicks the pants off 2.8, and I would even pay to watch that competition!!