are all dragon quest/warrior games the same?

[cloud1161]

dragon quest 8 for the ps2 was the first of the series i played and i really enjoyed it.  i played dragon warrior 3 (i think its 3) for the gameboy color, and got about halfway then couldnt really play it cuz it felt like i was playing the same game.   then i started dragon quest 7 for the psx and barely made it to the second town cuz it felt too much like the other two.  now i know since they are the same series they should have some similarities, but the battle system hardly changed at least between the three games i played.  i ask this cuz ive been contemplating getting the one that just came out for the ds but idk if i should if its just gonna be like the rest.