I think what is important in the glitchless category is the barrier for entry. Some players can have trouble with boundary breaking, various boosts, and skips. Diving is a mechanic that a player on their very first journey can learn and utilise without breaking the game. Making a distinction between diving for gaining speed in flight and faster descent, and diveboosting for the purposes of skipping sections (See: https://www.speedrun.com/Journey/run/2yw8xony the part in BB) and boundary breaks doesn't seem like it would be too difficult and would allow a few more different paths and angles for the glitchless category. For now diving as a whole is considered a glitch even though it is an intended mechanic, and seems counter-intuitive for a community concerned with speed. In my opinion something should be considered a glitch if it isn't used or likely to be uncovered in "regular" game play. With the release of Journey on Epic Games Store and the upcoming Steam release I believe it would be beneficial to the community overall for the rules to be reconsidered.