In my opinion, this size is sufficient to consider it a dragon. If we want to make it larger, we would also have to enlarge the competitors – the titans (currently 3 times the height of a human, as depicted).
So, if we want epic battles, we should enlarge the dragons/titans and increase the number of smaller units (tier 1-5). The question is whether it is worth doing, because to reach a truly epic level, we need to increase the size by a factor of 100, and it is unlikely that one dragon will be enough to defeat an army. Currently, in the name of epic scale, units with less than 10k hit points are no longer considered troops, and medieval capitals suddenly grow to a million inhabitants.