There are several things wrong in your post.
First off the 2 HB mids can't be compared. I can't camp the spawn from mid in the Nar Shadda HB map like I can in Quesh. To stop the ball carrier form scoring in Nar Shadda I have to move. In Quesh I can sit on top of that pipe all day and stop people form scoring or just farm damage. It's also extremely easy to score from there.
There is also only one way to get to the sniper/sorc/merc, a long uncovered walk down a skinny pipe. It's very simple to knock people off, stun/root and burn them down. There are several paths someone can take in Nar Shadda to get to any point on the map, as well as being randomly dropped there by the air ducts.
The reward v risk is skewed greatly in to reward territory in Quesh. There is literally no reason for a ranged class to be anywhere but that pipe. You're in perfect position for a pass, you at no point lose LoS or range on the ball carrier as they walk up the ramp, you can camp the spawn, you have easy access to a health pot and you're hard to get to. The risk is... nothing. The only thing that can hurt you up there is other ranged, who are standing possibly in the middle of your melee so I'd rather be up there than down in the scrum with the PT's, Mara'a and Sin's. In Nar Shadda the catwalks are great but not perfect. You can be LoS'ed, people can get out of range especially the ball carrier if you are on your side, you have to keep moving to keep up with the ball and you are in a prime spot to get pulled/pushed into the fire traps. These risks don't exist on the Quesh map.
Snipers can't even be leaped to or pulled down. On my Merc if I saw a VG I popped HO and laughed as he wasted his pull or netted a leaper and blew them up. It took concentrated effort from at least 2 players to get me off of there, as a Merc, Snipers will be even harder to get down once you throw in Entrench, new Evasion and the standard cover mechanic. To me that is making it to easy of a decision whether or not to go up there.
Something needs to be added at the least to the area by the acid traps for LoS because as of now it's way to simple for ranged to get on that pipe and never come down, with little to no risk involved. It's not even a 10 second walk to the goal form there. It's not even hard to get on. You can walk right out of the spawn on to it.
Honest question here (I didn't play the map on the PTS): Can't you stealth your way up and use knockback on the sniper to force him down ? Entrench is not up 100% of the time, just push and watch him gets eaten by the melee in the middle.