Strengths: It's Coke.
Weaknesses: It's not Coke. When it was launched, Coca Cola had suffered a huge backlash with "New Coke" It nearly brought down western civilisation as we know it because Coke was an established iconic brand and the "New, better tasting Coke" wasn't the Coke which had made the world a better safer place!!! Messing with the original brand was dangerous.
Opportunities: Well, 3 Billion coke drinkers like something about the company, so if the new product does not eclipse the old, then there will be additional sales to be made on top of the core brand by people who wanted their favourite drink without the hassle of mixing it with a vanilla shot. Research had shown that customers did mix coke with other flavourings. Hence you can see where lemon, lime and cherry came from. The true opportunity was in the convenience of having Coca Cola Inc do the mixing for them.
Threats: Pepsi would do the same. The new flavour would be denounced from the pulpit. An asteroid would crash into the earth. The first one was real and never materialised. The others were mitigated by strongly promoting the original classic and reassuring the customers that the brand was safe, regardless of what the kids wanted to drink.
Segmentation: People with an even less sophisticated pallet exist ? ergo ? quench their thirst. Promote by extending the franchise on the brand. Don't attempt to replace the brand. Target the sweet tooth. Placate the dental and obesity lobby by pushing 99% of sales into the diet category.
As to you doing it, take the advice given, don't emulate Coca Cola. You don't have a billion or so to get your brand off the ground. It's hard to think of something novel these days, but if you are in the fizzy drinks industry you m ...