The problem with that approach is that as you advance in tiers, the guns get more and more accurate and the shell speed increases so you don't have to lead as much. Its true the tiger can't track you at full speed..... but only if you're close enough to it. I've sniped enough leopards and a-20s to know.
Here's the catch 22...
If you're scouting out early, your sniper tanks won't be in positions and your arty might not have even loaded their shells yet.
Then... you must be fast enough to scout, but in cases where you need to be fast the tanks are usually big enough to have accurate guns that will kill you easily from a distance. Plus you'll usually be traversing through the open in order to get to enemy positions, giving TDs more than enough time to wreck you.
You're right though, most of my exp is from detection and the occasional pot shots. Yesterday I rammed myself into 2 arties and killed them both, was the most satisfying thing I've done.
Of course the other team had a KV-3 that nobody on our team could hurt so that game didn't end well for us either... >_>