This doesn't happen because I suck or don't know what I'm doing, it happens because you can't do much when you get 1 shot.
This is the fundamental problem, and it doesn't concern drg only but all melees, as we can see with all the /shout asking for a lot of things but melees.
Ranged DD have the big advantage of, well, attacking from far. Melees don't have anything to compensate.

Most MMO don't have this problem because they use a lot of attack pattern targeted to ranged/mages, like attacks that only hit players that are far away (even if it does break a little the idea of being a ranged dd in the first place).
It's a shame but we need something ridiculous like a big boost to the hp, magic defence and/or magic evasion of all melees.
Or, if we think about dragoon only, give us some mean to spam super jump to avoid aoe, or give us far more defensive/healing ability with /mage.

The balance of this game has always been trash, especially this aspect, but since they're planning a new release with the "native app" from Nexon, they need to improve it and the best way to do it is to do it now with the current game.
Crappy balance was more or less ok in the past because of novelty or stuff, but now people don't like to lose time, so they don't like to level up a class and learn hours later that said class is useless, thus people hate lack of balance. The native app is doomed to fail if they don't improve the balance drastically.

They can reduce the recast of Call wyvern all they want, they may even remove it completely, it won't change the fact that melees sucks and die all the time.