Stardust dragon attack cooldown

I have found that the only class stardust dragon is very good for is summoner. The reason for this, is that at least when it is short, it stays on top of enemies indefinitely, damaging them. This is good isn't it? Wrong, at least for bosses. Because the dragon is damaging them, their invincibility, short as it may be, is always in use, so you can't use your other weapons. Summoner doesn't really have this problem, because the dragon is their main weapon, although I imagine it might make teamwork not work as well.