Help a DM with a stealth problem.

[Neonchameleon]

He's doing it right; any turn a rogue doesn't get Combat Advantage is a bad turn. Brutal Scoundrels get it a little less. But only a little.

(That said, I'm still not happy with the idea of a rogue carrying a superior crossbow with the weapon talent and remaining balanced with the dagger wielder - but that's a playtest mistake IMO rather than anything he's doing wrong. And rogues don't get many +[W] attacks anyway)

 

[Arlough]

I'm going to side with Robtheman.
If you want to curb this a little, and/or add an element of danger for the Rogue, have creature begin preparing actions that as soon as they can spot him, they charge, fire, or attack in some way. The loss of stealth happens when the attack happens (and, technically, before the damage) and therefore the prepared action would interrupt his turn and the attacks would happen before he could hide again.