Umm, no.
If they're recovering low, your untechable ledgehop Bair and untechable needles should ensure they die pretty much every time, angles notwithstanding.
Battlefield is fine for Sheik because her SH aerials go through the platforms and she's not awkwardly forced to land on them. It's a reasonable size for camping or playing defense vs slower characters, but not so big that you can be viciously camped out by a Falco or whatever. It also gives her more flexibility with recovery, since landing on a platform sometimes can rob the opponent of their best punish move. The boundaries help Sheik, because she kills primarily by edgeguards and they don't affect her vertical KO percents too drastically. Being able to combo to the top platform because of the nice platform layout is also really good and winds up extending combos vs floaties/mediums really well.
The ledge thing is really more bonus than anything else.