I haven't played tons of 4e, just a few encounters and thought about it a lot, so perhaps you've found something I haven't.
Well, the games only been out for 2 months, and these rules for a little over a week or so, except for the stuff that just wasn't in the compendium, so nobody has played with any of them tons. But I've played quite a bit since release, including combats on the same maps with both sets of of rules since the the compendium update.
But you mention that rogues should use a combination and I wholeheartedly agree. From what I've seen on the boards people are saying that fights are usually done in less than 10 rounds. Certainly at lower levels a rogue is going to have to do his At-wills often in a combat, whether or not he's stealthy or not. So why not do a few Deft strikes from range, stealthily move to another hidden area 6 squares away with no movement penalty with Fleeting ghost to get a better angle at a new enemy, Deft strike, then when the defender moves into a suitable position charge/move out into a flanking position to get Combat advantage. Then when you move towards the controller in the back use your Encounter to daze him, then next round hit him with sly flourish while you have CA on him.
To perform your role as Striker (doing a lot of damage to a single target), you need to be getting your sneak attack damage on almost all of the attacks you're making, even at low levels. You can do that with deft strike at range sometimes, assuming you have a conveniently located area to get get total concealment and/or superior cover, which is the problem. Without conveniently located total concealment and/or superior cover, you can't get combat advantage from deft strike at range reliably.
You can't move stealthily using Fleeting Ghost unless you are already hidden and have concealment or cover along the entire length of the path you move, or end up in a square that grants you total concealment and/or superior cover (unless you use the reading of Fleeting Ghost that allows you to make a Stealth check as part of the power, which allows you to end up in a square with cover or concealment without necessarily needing cover or concealment on the way to it, though it would be helpful).
Now, you're moving into a flanking position, which is fine, as long as your party has cleared out all the enemies not locked down by the defender. Otherwise, you're the prime target for any enemy not locked onto the defender (such as the artillery) and the guy you just hit (and/or other monsters locked onto the defender) is providing flanking on you for any and all lurking skulks or skirmishers running around.
Now, if you waited all this time to go after the Artillery (the monster version of controller generally, though you might also be out hunting down skulks and skirmishers to keep them from putting too bad a hurting on the fighter or jumping on your controller), by the time you get to him the artillery has unloaded all kinds of status effects on your party (and most likely you, and it's hard to go after him after you just sucked up a gluepot or stink bomb) and at that point, why bother, since the whole party is either dead/immobilized, or charging past you to do it themselves.
The way you played it isn't fighting like a rogue, it is fighting like a fighter. Attack what's closest to you, let everything come up to you, then move forward when everything around you is down. Forcing the rogue to do that makes it just a fragile, second-rate fighter. It doesn't perform like a Rogue should, engaging the enemies with which it has a favorable matchup while avoiding those that are unfavorable (until circumstances change and they can re-engage with an advantage).
If you need to take out the artillery as a Rogue, what you should be trying for is something like (using what I gleaned of the situation you described and the reading of Fleeting Ghost to allow a Stealth check):
Round One: Piercing Strike with shuriken or dagger on a target you can hit, hopefully getting combat advantage from First Strike on something that isn't a minion to soften it up for the defender. Follow with a move to a place with cover and/or concealment (or better) and a Stealth check using Fleeting Ghost. Or, double move, making two stealth checks, to close on the artillery. Make a perception check as a minor action if you have one left (shuriken or dagger or whatever was readied or you have Quick Draw if you made an attack) to locate any hidden skulks, skirmishers or artillery. Consider making some sort of attack via an action point, but this is likely too early, as you'll be left exposed and almost certainly need at least two attacks to do your job, and you'll want to be hidden to avoid getting pummeled.
Round Two: Attack the artillery if you can, gaining combat advantage from being hidden, then move and hide using Fleeting Ghost. Consider using an action point to make another attack if you have a power that has a chance of making a kill this round, but remember that doing so will leave you exposed well away from the rest of the group, so be careful. Again, burn a minor action if you've got it to look for an enemy.
Round Three: Make your second attack on the artillery, with combat advantage from being hidden. If it hits, this should kill most artillery at low levels, though you may need to run to a third attack on something particularly tough or if you roll poorly. Again, burn a minor action if you've got it to look for an enemy. Regardless, move and hide using Fleeting Ghost.
Round Four: If you have to, attack again. Otherwise, your last move should have you headed back to the group. Get back to the group to heal up and/or help out. Focus on cleaning up skirmishers/skulks or look at flanking the toughest thing the fighter is facing so you can hit it with something like torturous strike or something that will give it a debilitating condition.
If on any of the rounds you blow your Stealth check, odds are you're going to be hammered by the Artillery and anything else that is around. You also might take some damage just because it isn't hard to guess where you're at when you move and hide after attacking, since you aren't hidden during the move, so bad luck can put you in the same banged-up boat as failing. Regardless, if you take a big chunk of damage, break off your attempt on the artillery and fall back to the group if you can (getting hidden as soon as possible to facilitate getting back to healing). If you get hit with an immobilizing status effect, pray. Even if it takes you three or four rounds to get the kill or you fail, if you've been hidden between attacks, the artillery has probably wasted shots trying to hit you.
I don't see what's so bad about sneaking around a bit to flank enemies and get into good position and then use all your rogue bad of tricks.
Because standing in one place beating on something is fighting like a fighter. And if you want to do that, and can make it work, or enjoy it even if it doesn't really work, that's fine, but you shouldn't have to play a rogue that fights like a fighter.
I've seen the rogue in our campaign use Sly Flourish over and over. My character used his at-wills over and over. That's what ya do.
Tellerve
If you really like that and the player playing the rogue is satisfied with playing that way, I'm glad you enjoy it, but having played and watched rogues that moved around the battlefield using all of their abilities and skills, and attacked using a variety of weapons and powers on a variety of targets, that feels like a big step back.
It definitely doesn't feel like:
"Rogues are cunning and elusive adversaries. Rogues slip into and out of shadows on a whim, pass anywhere on the field of battle without fear of reprisal, and appear suddenly only to drive home a lethal blade."
