Yep, this is one of the big problems for me. The entire point of doing a crossover is memorable and familiar characters. The game lends itself really well to expressing traits and such. But none of the DQ characters stand out to me enough for me to want to grab the game immediately. Admittedly, I'm not incredibly familiar with the series, but the characters just didn't seem as strong as some of their other choices.
That said, Hyrule Warriors is brilliant, and Koei Tecmo did a fantastic job translating those characters, so I think we may be prejudging them harshly, and they may portray the DQ characters just as well. I really hope they keep up with the crossovers. I really, really want to see Fire Emblem Warriors.