Re: could they do a show with "realistic" aliens?
There was a Arachnid Starfleet officer in the novel Wounded Sky.
There was also one in TNG, this excellent webpage
has the illustration and evolutionary scematic.
"The first duty of every Starfleet officer is to the truth" Jean-Luc Picard
"We can't solve problems by using the same kind of thinking we used when we created them." Albert Einstein