Thanks to the Warbot P Armor I can now make a pretty deadly build involving bunker. With that Armor enhanced +8 tech, Charfade's Club enhanced +8 tech, Plasma ACP and Cupid's Sorrow, I have a +55 tech bonus, which is pretty insane. My 5 focus build means that with 100 tech my bot is doing 61-65 and bunker does a minimum listed damage of 59 plus the 5 from focus. I have actually crit 70 with it on a level 25 before. I go with P Armor as most 2v2 are artillery mercs, and with my current build i therefore have a minimum of 45 defence, so even if I get smoked 30 dex, it's still 35 xP. My resistance has no additional bonuses, but at 37-45 +1 is still quite high.
In regards to the bunker discussion, personally i think like most skills it's like marmite. As a merc I love critting with it, but I've also been crit with it with 45 defence for 40 damage, which makes me also kinda hate it. Bounties hate it because it ignores shadow arts. But similarly they themselves have a love/hate relationship with that skill in regards to blocking another player or being blocked by an enemy bh.