I know the stats don't tell the whole story, certainly at that level, but the O's are well represented on the pitching side. In addition to their top 3 that you mentioned, they have another 5 or so guys in the top 50 of the league era-wise.
That hitting side is the complete opposite. Sorted by OPS, besides De La Rosa, who is about 15th overall, the O's don't have another guy in the top 100 it looks to me.
While there may be some environmental factors involved, I think it is safe to say the pitching for the O's in the DSL is more promising.
