Ves generally disliked repurposing his work.
The Giant Killer was originally designed to serve as the exclusive ranged mech of the Penitent Sisters.
When Ves poured months worth of work into the design, he never thought about sharing it to other Hexer groups. Neither the Hex Army nor the Glory Seekers were meant to harness this new model.
Did he think about it? Yes. Why shouldn't he? The Penitent Sisters may have joined the Larkinson Clan, but they still clung to enough Hexer traditions to remind everyone of their origins.
Theoretically, it was doable for Ves to develop a variant that possessed a character that was more compatible with normal Hexers.
Was Ves willing to do it? Not necessarily.
Aside from all of the other reasons he mentioned, he also had an additional objection.
"I think it is rather disrespectful to discuss such a profound change without listening to the input of Juliet Stameros."