Allow clips to have an 'anchor' when synchronising
Often when I'm syncing two clips (one on video 1 and the second on video 2), once the audio sync is done, it will move the V1 clip along to match up with the V2 clip (which remains in the same spot). This can be super frustrating when the stuff in V1 has been set up perfectly and am just trying to slot in the new clip in V2 to be in line with it, but now the V1 clip has just overwritten something else in that part of the timeline.
You should be able to anchor any clip you want in the sync process so that that it will stay where it's at NO MATTER WHAT and the other clip you're trying to synchronise with the anchored clip will just slot in to where it lines up with the anchor.
(I know there's a workaround which is to position the V2 clip behind the V1 clip so the end of V2 is "further back" in the timeline than V1 but this is not an ideal way to go about this problem as there can often be things in the timeline that you don't want to alter when moving the V2 clip "behind" the V1 clip)
i'm bad at explaining things concisely so here's an article that is also frustrated with this problem if I didn't make sense: https://forums.creativecow.net/thread/3/961233