I think its a huge change that fixes one of the two biggest issues facing 8th. The problems involving the Alpha Strike are huge. If you have built your list right,you can cripple your opponent first turn.
The biggest changes are that it forces you to have half your points on the table turn one while also removing ANY option to put models closer than the deployment rule's minimum distance, normally 24" through any means. This means you won't get 64 bolter shots and 24 assault cannon shots pummeling your deployment area when Deathwing arrives. You won't have a 30 man bloodletter unit deploy from deepstrike and tie up half your line.