What level are you playing at Frostei because in diamond all Vaynes I see go Blade - PD - LW - IE/Defensive with no BT. Unless you can get away with BT (i.e, no champs that can zerg you where Blade helps the most) and even then, only people who are super comfortable on Vayne will go BT. Vayne is my most played champ by a long way (1000+ Vayne games, 2nd highest champ 300 games) and I build Blade PD LW almost every game because it's just safer.
You can only trade as Vayne if you're better than your opponent really. I can tell almost instantly if I'm playing someone below plat just based on how they trade when they're against a Vayne. Against people of equal or better skill, you're likely to lose most trades but it also depends on the supports as well.
And yes, everyone runs heal. It's objectively better than barrier.