But (unfortunately) all to soon, he simply becomes a rubber stamp officer, Janeway's lap dog, permitted his animal spirit guides, his own little adventures but not much more than that. I call that loss of potential.
As do I.

That's an important growth point, not to be underestimated. But if that's all there's to show for 7 years, it's kind of meagre.
For a character with Harry's potential, it's kind of crap. And the lack of promotion was a deliberate and unnecessary insult.
That tells me Behr was the one more on board with Sisko getting promoted. And to give Brooks more free reign.
Avery Brooks preferred the bald/goatee look, but he had just sported it on "Spenser For Hire" as Hawk, and he was kind of iconic. So when be played Sisko, they wanted him to look different. Once Sisko was more established, they let him look the way he wanted to look.