Back in the day, there was a partner who would send me PowerPoint presentations and ask me to add some "sizzle." He knew I'd been to design school and had worked with me on a number of web development projects, so he figured I could add some lipstick to content we were going to share with clients. The problem was that in many cases, the flaws with the decks were structural and no amount of glitz was going to cover that up. If you take a shitty purse and bedazzle it, it's still just a shitty purse that's covered in rhinestones.
More recently, the group I'm in now was approached by another group to "jazz up" a program they had developed to encourage flexibility in the workplace. The problem was that the program was so rigid and full of compliance exercises that the execution of the program was almost antithetical to flexibility. They knew the program wasn't right, but they thought it was just lacking oomph and that we could add some spectacle to make their compliance-heavy dog of a program more exciting. Their thought was that if you throw enough money and pageantry at something, it will automatically become fun.
When we tried to back them up and get them to re-think what they were planning in light of what they were trying to accomplish, they pushed back on us saying that "we love you creative types, but we know what the answer is." That was a big red flag to our team.
I always try to impress upon people coming to me late in the game asking me to sprinkle glitter on a turd that, while I think creativity and design can help them, design is an architectural effort and all creative decisions need to be traceable back to a strategic objective. I tell them that design is not fluff and introduce them to the architecture concept of the parti pris. I tell them that once an architect has made the big decision, the underlying principle of their efforts, all the creative decisions that follow become that much easier to make. If all your creative and design decisions are based on a central organizing force, the result will hang together in a way that the components all make sense in light of the whole.
There is a reason Apple's products are (as the UK High Court determined) cooler than their competitors. It's not about a thin veneer of glossy icons and rounded corners, even though the anti-fanboys would have you believe that. It's that Jony Ive is one of the greatest designers in the world and he ensures that every facet of the design holds true to Apple's philosophy.
Design and communications are not afterthoughts; they are more than a coat of paint and theatrics. For design to be truly successful, the designers need to be plugged into the original intent. If the designers start the journey at the beginning, then the decisions they make along the way will stay true to that original intent and the result will reflect that in a way that is naturally cool. No need for artificial "sizzle."