I've played both the Imperial side and the Republic side through Taris and the idea of saving Taris seems silly to me.
So, the Imp side wants it fully destroyed to "remind the Republic of it's failure." The Republic politicians want to save Taris, thinking they can reclaim it. What's funny about that is, if you talk to most of the Trooper npcs, they wonder what the point is too.
Speaking of politicians...
I personally side with the Imps. The planet just needs to be put out of its misery. When the Republic finishes its studies, they should bail out too. The planet seems so damaged it's beyond repair.
Taris is worth saving, even though it costs precious time and resources, it will remind the galaxy of the Republic's power and determination. And if any Rakghouls come along i'll either