The biggest issue with the Foiler is that most of Trooper's secondary weapons are ALSO passive, meaning things like banners and boots are just a liability, the intent with this buff is to make all secondary weapons viable

Banners can be activated and charge faster

weapon swap speed so you can actually combo what few weapons you have left

And the boots at least grant a faster swing rate, letting you pick between more safely going in with your melee (Mantreads) or going in with better attack speed while vulnerable to airblast (Gunboats)

After all, you ARE sacrificing your mobility, crowd control, damage, and range for the vest, so I think this would work pretty well