As pointed out by others, there would be downsides to making Totemic Projection work like Trap Launcher, with niche situations that would prefer both versions. That is basically the perfect thing for a Glyph.
However, that is not the situation for Shaman. We do have a lot of totem related abilities, the totems themselves. This is going heavily off topic, the whole point was that Warlocks and Hunters are generally assosiated with being pet classes (as Shaman are with being a totem using class) and Blizzard has given some of them the ability to not use pets. That wouldn't really translate well to giving us the ability to not use totems, because you can't really just go 'No totems, have X% more damage' as - at least the Earth and Air Totems - aren't really throughput abilities, they are a massive part of our utility, much more so than pets for Marksmen/Survival (paraphrasing a quote from the Hunter thread, 'yey a talent to get rid of our DoT with an AI').