Well, right. He can't really do much aside from aiding astronavigation, and that's the problem. The fluff isn't even clear on whether the guy's still alive in any meaningful sense. Without the Emperor, there's no single person in the Imperium who's clearly in charge. Various factions therefore have roughly equivalent authority, and they often have conflicting priorities. Worst of all, there doesn't seem to be any form of arbitration between these factions. It's a damn mess.
And that's part of what makes it so fun.
