Is there anywhere else to go from here...

Wouldn't work. Vaginas aren't always the same size and shape. As a woman becomes arouse it lengthens and widens to accommodate a penis. You couldn't just pour something liquid in there and expect it to look like anything or be shaped like anything. I just don't see how it would be physically possible.

I've heard a lot of guys say the sleeves aren't very realistic.

I do think they could create a more realistic product, but I don't think just one mold would cut it. I think they could do a lot with more realistic texture and heat and shape accounting as best they can for elasticity.

I would like to see them try