Yeah, his engineering is based on Warpath but it is otherwise a whole new sculpt so he could end up any size - It is not re-using any Warpath parts. Unlike the MP Seekers, Presser is actually a whole new mold that happens to follow similar transformation design to Warpath.
If you check the details, the whole thing is a new sculpt with it's engineering heavily borrowed or 'inspired' by Warpath. My hope is for him to be around the same height as Defender.
It's engineering is not original but I don't think that Hasbro would hold any IP rights to that. Well it's not as if IGear would care anyways.