Most obvious deficite is lack of any bypass capacitors. Secondly, separating grounds without filtering supply lines is dysfunctional. Finally, even if you have perfectly filtered and noise-free supply voltage on each block, single ended signals crossing block borders ("digital control signals", "single pulse" above) will be affected by additional ground bounce.
I seriously doubt usefulness of the presented concept. Separated ground isles can be useful in specific cases, e.g. for switching regulators to keep commutating currents inside the block. They involve filter chokes for supply in- and output lines crossing the border.