Most of Gen 3's cries are fine, all but one of Gen 4's are fine, all but like, two in Gen 2 need to change, all in Gen 1 need to change, all in Gen 5 are fine. Lugia's and Ho-Oh's cries don't need to change. I think they're fine. Off the top of my head I can't think of any in Gen 3 that need to change but I'm sure I'll think of one later (Rayquaza, Aggron, and Salamence do NOT need to change. Those are too epic). Arceus' cry is awful. It sounds like three Gen 1 cries stacked on top of each other. CHANGE IT.
Aside from that, keep all the cries the same.
I'm not easily impressed; I'm usually oblivious to whatever's in front of me. Stunfisk is the epitome of monstrous majestic legendary creatures that spew fire.