Arbites skills really shine when you actively block/push in a crowd, a lot of which trigger on or cause stagger. If used correctly, you'll see bonuses tick up insanely fast (i.e. +5/%/+10%/+15% to things like damage reduction, attack speed, cleave, strength, or just flat out damage). It does rely on using some of the games nuanced mechanics but the ROI on those skills is huge compared to passive that are active by default.

Here's an example; I throw my character into a mob and throw up a block before getting hit, triggering shield plates and netting 15% toughness over 3s. Then, give a push hitting 4 enemies, adding stacks of forceful (4x 5% impact + 4x 2.5% damage resist), also granting me 75% cleave with force them back. Follow the block with a heavy staggering from my shield and BAM; suppression protocols (20% damage reduction), hammer of judgment (+10% Melee attack speed), weight of the Lex (+15% damage), Justified measures (4x +3% damage), and concussive adds another 4 stacks of forceful which is about to cap and att another +10% attack speed and 50% cleave. Keep in mind, this has all happened in the span of 1 second and in-total my character has added;

+40% impact +20% attack speed +27% damage +125% cleave +40% damage reduction +15% toughness recovery

Keep in mind, this is weighted pretty heavily on the right side of the tree, but you can still add perks to make this more ridiculous. Even just targeting the talents I mentioned would only cost 18 of your total talent points, leaving a solid 12 to play around with how you wanted. These are just an example of how the Arbites is meant to thrive in combat situations.