Warhammer 9th Edition: Everything You Need To Know
8. Modifiers Are Capped At A +/- 1
Thankfully Game Workshop acknowledged that the ability to stack modifiers on a single unit was harmful to the game.
The sheer frustration of getting a – 4 hit modifier against a Lord Discordant, who is larger than your average London cab, and it being impossible to hit him until it was too late was palpable.
With this in mind they levelled the playing field and introduced a capping system. This means that even with +3 to hit, it will only convey the benefit of +1. However, this does not mean that having +3 to hit isn’t good!
With all the terrain rules and racial abilities of different factions there will be times where you will be suffering two -1 to hit. Your +3 will help cancel this out and still provide you your capped +1.
In a nutshell, stacking multiple +1 to hit buffs is still great because it will allow you to ignore terrain and other negative modifiers but you’ll no longer be able to run a model the size of a large car and it mythically be unhittable with a Missile Launcher.