The crystal on the heritage is domed, and sits higher than the SMPs crystal. Despite being taller on paper it wears less chunky.
Rolex uses completely flat crystals with very little above bezel rise. I can't speak to the 6 series actual thickness and I hope somebody with some calipers and a 6 series chimes in, but the 5 series (date) is 13mm tall with a flat crystal. I don't recall height between the 5 series and 6 series being a discussed issue. Whether that is because they have essentially the same height or because when you are comparing Rolexes to Rolexes height isn't worth talking about (
😎 ).
While I absolutely agree that the dressy aquaterra should be shorter than 13 mm, it's worth pointing out that if the Heritage had a comparably flat Crystal to the Submariner it would be very, very similar to a 5 series in height.
This isn't really a criticism of rolex's flat crystals, there isn't anything wrong with them. However, don't crystals give a different visual look and absolutely recall the vintage style. Vs the original SM300 @14.2-14.5mm tall @300M water resistance I'd say the heritage is proportioned incredibly well. (the shorter 165.024 had only 200M water resistance)