Dallas did trade away Mabrey and Gray signed with Atlanta so two starters are gone, but the trade brought in Diamond who just happens to be 6'1" as well. And I get the 'BPA' mentality of drafting, but that makes more sense in team games with larger rosters. With 5 fairly clearly defined skill set players on a basketball court, taking four identical size/skill players in a single draft is just weird.
And it isn't like there were not other good options with different size/skills - I think both Dorka and Amihere were undervalued in the draft and have a chance to outperform their draft spot.