No, there's an art and skill and subtlety to communication and the human mind. It's not just the written word. Speech has just as much nuance.

I know Latin and Japanese fairly well, in addition to handfuls of words, sentences, songs, and poems in many other languages, because it is a hobby of mine. I have found that there are words in these other languages that English does not have an equivalent for. When I think of something really, meltingly cute with a child-like simplicity, I use the Japanese word kawaii. Adorable and cute are not quite right. Similarly, mu -- unask the question -- has a certain connotation and elegance to it that 'unask the question' lacks.

In the same vein, <3 means something to me that an English word cannot convey. :D is different than :) and =), too. There are subtle levels of happiness and silliness there. They are complex. They change with context. They get a message across consistently. The fact that they are made out of punctuation is the only thing that separates them from a word -- and honestly, even words and letters are just stick drawings anyway. A letter just happens to represent a sound. Why is it superior? It seems a little arbitrary.

Yes, we have a dictionary to agree on a letter's pronunciation and its related words. We just don't need one for emoticons, because they're generally so obvious. <3 is heart and love, but my social circle has a nuanced definition of it unique to us -- just like we have an certain nuanced definition of the word taters.

Yes, people can use emoticons to be mentally lazy, expressing generic 'happy' rather than a specific level of happiness, but they can do that in words, too. People will be lazy no matter what. You can't blame the tool for that.

Are there other objections?