I still want the trio to be Kirk/Spock/McCoy. I want the bromance.
That's my only objection to the Uhura/Spock thing. I think they can still do both though.
The girl in the couple in 'Balance of Terror' had to move sections so that she was not under her husband's supervision.
I think romances between shipmates is inevitable as are workplace romances where I met my husband.
The problem between Spock/Uhura would be if Spock gave her undeserved good grades or refused to let her on dangerous missions. We can see in STID that Spock insisted Uhura be allowed on the dangerous mission and it was Kirk that objected.