Nitpick:

Here "Crank Fizzlebub" has a bigger font than the rest of quest givers, but he's not more important... I suppose this happens because his name is interpreted by the code as the header of the tooltip. I think either all quest givers should have that font size, or none at all.

v5.4.0

This is unfortunately simply how the GameTooltip works and we can't do anything about it. The first line will always be bigger than others thanks to Blizzard 😞