Once upon a time i tried to learn how to proc fc wtih 100 % success rate. Eventually i gave up but learned to proc it with decent rate anyway. Based on the fact that you are not doing anything while you are channgelling it, it should of course take as little as possible time to proc it. Its fascinating just how long some mobs can hold their weapons or whatever in action animation without actually hitting you.
But this was about daggers. Leaps have been mentioned alot and at this point their existence is just a "kitten you" but we can live with that, we are warriors. Daggers target caps go 2 1 1 1 5 1. The weapon itself is maybe best compared to greatsword, both have decent damage with some utility (evade/movment, might synergies for gs and movement, cc and some might synergies on dagger). Greatswords caps are 3 3 3 1* 1 5. Axe, still the pure dps option is 3 5 1 3 5 1. In general, dagger tries to exchange high target caps for better single target damage. Arcdps players can tell us how this ends up, but for general pve its clear which options are more "fun".
Dagger skills 3 and 4 next. 3 dazes and and stuff happens if the enemy is using a skill. Proccing this can be impossible or doable. Just look at that leyline anomaly and tell me which part of its animations are attacks. Extra daze might or might not be useful so its not a great loss if this doesnt proc. 4 does damage and moar numbers if the enemy is not using a skill. Theres also ½ second of casting time so you have to glance into the future and know when the enemy is doing stuff. Or maybe the IsAction check is performed at your keypress. I have no idea how this mechanic really works. The payout - double damage is noticeable (if you are looking at the numbers on your screen) so it would be nice to also learn to proc this always. 5 seems to go to full cooldown when interrupted (i have just noticed this few times, havent actually tested if thats true) and while its satisfying skill to use the cooldown could be alot shorter because of the "combo" problem with daggers. The combo is that 2 leaps you to your target, 3 interrupts them and 4 does damage because they are hopefully still dazed. Out of 5 possible skills you just used 3 and now you can press that 1 very very hard or throw the 5 at something if you feel like it. Especially using 3 and 4 in succession feels just like the classic gw2 game design - heres a button that does nothing useful but you can press it to get 20 % moar numbers for 5 seconds at a 30 second cooldown. Wow much fun. As a side note, those "on skill use" and "not use" triggers are quite rare, does any other weapon have two of them?