Tasha would of stayed in security, it was her karma. If she didn't stay Datas' lover, she would of become his best friend instead of Geordi. She would of been the one to help Data with his journey towards human understanding, and as a women, better equipt in explaining emotion and feeling.
Worf would of become chief medical officer after Dr. Crucher left for Starfleet medical, instead of Dr Pulaski. Remember what a fine job he did delivering Keikos' baby?
She would've wound up on Deep Space Nine instead of Worf. -- RR
And hooked up with Jadzia instead of Worf?
God that would of been so hot.
This could of been Star Treks' chance to show a long term, well thought out gay relationship. Not a passing story line blurp, or fanfic slash, but something that could of started slow and developed over more than one season. Tasha could easily replace Worf in many episodes.
Rule of engagement would have been better with Tasha in charge of the Defiant, and on trial, facing a death sentance in the Klingon empire.
Looking for par'Mach in all the wrong places, both Tasha and Jadzia could go after Grilka (Quarks wife), perhaps resulting in a offscreen three-way, which would of sent all three of them to the infirmary.
They would of eventual have been married, bringing gay marrage into the DS9-verse.
At the wedding both Tasha and Jadzia, of course, would have worn red leather!
Change of heart is another episode that actual works better with Yar and Dax. Tasha the emotional, high charged security officer, Jadzia the more mature, thoughtful science officer.