This is my personal opinion and is very subjective, so I won't be offended if this wont be considered as an item for improvement. I say that the emoji characters should be changed. When I look at these emojis I have some reluctance to use them in the text because they appear a bit dated. Perhaps this may not be much of a concern given that I have not seen emojis beings used on a regular basis, unless if others feel less likely to use them for the same reasons which I dont use them. I would recommend a style used in the following emoji sets. It looks more pleasant to the eye and appears more modern. But having said this, this is just my own subjective opinion.