> This reverse traceroute is still helpful. The paths will be roughly the same, likely differing only in terms of which specific routers see your packet.
This is categorically incorrect. While the AS path is often the same, the actual peering points are almost always quite different. Most ASes use hot-potato routing - getting packets to the next AS at the closest peering point to the source of the traffic. (And even if cold-potato routing is used, that's still asymmetric). In addition if there are two options with the same AS-path-length hot-potato routing can lead to different AS paths. This can happen if there's two mutual transit providers between source and destination and various other situations.
This is categorically incorrect. While the AS path is often the same, the actual peering points are almost always quite different. Most ASes use hot-potato routing - getting packets to the next AS at the closest peering point to the source of the traffic. (And even if cold-potato routing is used, that's still asymmetric). In addition if there are two options with the same AS-path-length hot-potato routing can lead to different AS paths. This can happen if there's two mutual transit providers between source and destination and various other situations.
(EDIT: fixed hot/cold mixup)