Yes, most of the items on the invitation sent after scheduling a webinar should be by default. But, why not have some custom design available. For example, the picture of the presenter is at the bottom of the invitation with no reference to who the person is. Why not have a fill in box allowing for a brief title, introduction or description to go next to or under the picture so it is just not sitting there.
Also, A bit more design would help on the title of the event. It could be left as is, or possible enhance the color and size of font.
Please consider making the email invitation more inviting. Thank you