For now, we assume that a window can not span a branch. In other words, the window includes instructions only within basic blocks. We'll show how the window can be extended beyond the branch later. This determines how often a structural hazard results in stall. The presence of antidependences and output dependences WAR and WAW hazards limit the scoreboard more than RAW hazards.
RAW hazards are problems for any technique.
But WAR and WAW hazards can be solved in ways other than scoreboards.