Given that Lohner´s Emporium is in the works and the WoM weapons dont have illusions yet, this might be a good time to suggest this.
Basically, a kind of slender glaive/guisarme/fauchard/whatever you want to call it. As seen here in the use of imperial soldiers against trolls.
I think the current spear skin is a great fit for Markus Hunter career, but does not look quite fitting on the more heavily armored frontline Mercenary class. A slender glaive would look more militaristic, still fit the thrust-heavy moveset of the spear but also make the spear´s slashing attacks a bit more believable (as currently, chopping Skaven heads off with as small spearhead feels a bit strange). I´d say it would fit neatly into the mercenary aesthetic.
So, yeah, I think this would be a really cool spear illusions and a great fit for the Mercenary class, and something I would definitely want to use (maybe even pay for).