After a few sessions of D&D 4th edition play, both in combat stealth and the Prime Shot class features seem bulky or not "fun". The following House Rules remedy the situation.
The first house rule "No In-Combat Stealth" removes stealth from combat after any pre-combat stealth is broken.
No In-Combat Stealth
You can no longer stealth without the use of a power in combat situations (though you could begin a combat situation hidden).
A new rogue build that allows ranged attack based rogues to use sneak attack without relying on stealth. This build relies on ranged attacks versus unprotected targets from cover - Sniping.
Sniping - Rogue [deadly sniper] class feature
As a minor action, designate a creature that you have cover or concealment from as your target. If that target does not have cover from your attacks, gain combat advantage against that creature with ranged weapon attacks until the end of your turn. Allies are not considered adequate cover for sniping (though enemy creatures do provide adequate cover to avoid being sniped).
Replace the Prime Shot class feature of the Ranger with something more suitable (and tactically fun). Note that two-weapon fighting style rangers do not gain this class feature.
Covering Fire - Ranger [archer] class feature (replaces Prime Shot)
If you are prone, or have cover or concealment from your Quarry, you gain +2 to ranged weapon attack rolls against your Quarry. This bonus does not stack with combat advantage. Allies are not considered adequate cover for covering fire.
An additional feat specifically made to complement the Covering Fire class feature, though usable by anyone.
Steady Aim - Heroic Feat
You suffer no penalty to attack rolls from being prone when using a bow or crossbow.
Normal: You suffer -2 to attack rolls when prone.
Yet another rogue build - Knife Thrower, this time for throwing attack specialization. I admit it’s a bulky read but I believe it accomplishes the desired goal - to create a unique favorable positioning for throwing attack rogues that allows them to use the sneak attack class feature (without reliance on stealth).
Deadly Throw - Rogue [knife thrower] class feature
You gain combat advantage when you make an unobstructed ranged weapon attack against nonadjacent creatures. To check for an unobstructed attack, draw a line between the middle of the square you occupy to the middle of the square the target occupies. If the line does not cross any squares with cover generating objects your attack is considered unobstructed. Note that both allied and enemy creatures count as cover generating objects.
Currently to maximize defense the Warlock should move at least 3 squares every turn of combat to gain concealment. This is an optional class feature for the lazy warlock (lets be nice and call him a turret warlock)
Blend with Shadows - Warlock class feature
As a move action, you gain concealment until the end of your next turn.
At character creation a warlock can choose either Shadow Walk or Blend with Shadows as a class feature.
A replacement for the Prime Shot warlock class feature, that blends with their concealment generating ability.
Boon of Shadows - Warlock class feature (replaces Prime Shot)
You gain +1 to attack rolls when you have concealment gained from Blend with Shadows or Shadow Walk.
A new feat for those polearm users out there!
Second Line Soldier - Heroic Feat
You gain a +1 feat bonus to attack rolls against nonadjacent creatures when wielding a melee weapon with reach.

No In-Combat Stealth
You can no longer stealth without the use of a power in combat situations (though you could begin a combat situation hidden).

Sniping - Rogue [deadly sniper] class feature
As a minor action, designate a creature that you have cover or concealment from as your target. If that target does not have cover from your attacks, gain combat advantage against that creature with ranged weapon attacks until the end of your turn. Allies are not considered adequate cover for sniping (though enemy creatures do provide adequate cover to avoid being sniped).

Covering Fire - Ranger [archer] class feature (replaces Prime Shot)
If you are prone, or have cover or concealment from your Quarry, you gain +2 to ranged weapon attack rolls against your Quarry. This bonus does not stack with combat advantage. Allies are not considered adequate cover for covering fire.

Steady Aim - Heroic Feat
You suffer no penalty to attack rolls from being prone when using a bow or crossbow.
Normal: You suffer -2 to attack rolls when prone.

Deadly Throw - Rogue [knife thrower] class feature
You gain combat advantage when you make an unobstructed ranged weapon attack against nonadjacent creatures. To check for an unobstructed attack, draw a line between the middle of the square you occupy to the middle of the square the target occupies. If the line does not cross any squares with cover generating objects your attack is considered unobstructed. Note that both allied and enemy creatures count as cover generating objects.

Blend with Shadows - Warlock class feature
As a move action, you gain concealment until the end of your next turn.
At character creation a warlock can choose either Shadow Walk or Blend with Shadows as a class feature.

Boon of Shadows - Warlock class feature (replaces Prime Shot)
You gain +1 to attack rolls when you have concealment gained from Blend with Shadows or Shadow Walk.

Second Line Soldier - Heroic Feat
You gain a +1 feat bonus to attack rolls against nonadjacent creatures when wielding a melee weapon with reach.