The Scarlet shield is a good solid and reliable 3 star shield it's greatest fault is that it doesn't have a path to 5*.
It's resistance values are identical to the Twisted Targe, another status resist free shield. The targe however has a path to 5* while the Scarlet doesn't.
I would propose to create the rest of the line.
4*
Carmine Cover
This Shield physically resembles the Great Defender with red color and light tan border.
Damage resist values are equal to the DTS with Elemental instead of Pierce.
Instead of Sword damage Medium this shield would provide a health boost of +3.
5*
Crimson Castle
This shield physically resembles the Guardian shield with a "Heart Attack" symbol displayed like the 5* plate shield symbols.
Damage resist values are equal to the BTS with Elemental instead of Pierce.
Instead of Sword damage Medium this shield would provide a health boost of +4.
I agree with your post holy that having a 5 star version would really complete this shield because it has a great back story for it, the shield feels usable and would go well with the deluxe vita suit or a 5 star vita suit creation. I hope this can be implemented and lets cross our fingers for its 4 and 5 star counterpart to not be a reskin if it is created.