It doesn't bother me if a font and style is changed in a comic. I actually believe that changing the style and font sometimes is another level of creativity. It can be done for improvement, just like you are doing. It also can be to just add another level of artistic creativity. For example, In one comic I've seen different colors used for words when different characters are talking. This allows readers to know who is talking without the speech bubble being literally pointing towards the speaker. Another example is creatively drawing letters to match what is being said or the mood of the moment.