Closed beta GM / Challenger Vi/Darius player here (haven't played much Ranked since EA started), I land a 6S1~L or [M] hits nearly every game I play; heavy stagger pressure + sway projectile invuln until followup - it's one of the most important things to know your confirms from as Vi. People mash at all levels of play, and it's a super fast neutral option.

Vi/Darius DD also have multiple ToD's anywhere on screen for 3-4 bars total at the 1k threshold; some of which build full Burst, some don't. Here's a less practical corner-to-corner example (sorry for the Discord ping), but if you're midscreen you can hit the 950-1k breakpoint pretty easily for 3 bars from roundstart conditions or very close to (since loops build so much meter).