No, Dragon Quest Heroes is one of the easiest plats. Much easier then Warriors games.
Dragon Quest Heroes 2 plat is extremely difficult and frustrating on the other hand as I pointed out in my earlier post.
Take it from me as a guy with only 3 plats, Disgaea 5, DQH and DQH2. Of those DQH was by far the easiest.
Edit: Post in reference. http://gamrconnect.vgchartz.com/post.php?id=8601299
DW games takes a longer time to plat. DQH was relatively easy, except the Zoma Superboss.