If I were in charge of designing, say, a video game and we were trying to capture the spirit of the designs rather than the specifics of the rules, the Hellbringer would be the design where a bunch of clever engineers said
"look, 'mech survivability in combat is a holistic science. Think of the survivability onion; you try to avoid detection, if you can't avoid detection, you try to avoid acquisition, if that doesn't work, you try to avoid getting hit, if that doesn't work you try to avoid the hits from penetrating into important systems, and if that doesn't work, you try to avoid the loss of critical systems causing destruction of the unit. There's more to survivability than just armor thickness. This Hellbringer is designed around integrated stealth, ECM, active protection and smart redundancy. It's much more mass-efficient, and ultimately more effective than just blindly slapping on more armor!"
and whoever was in charge of procurement bit this, hook line and sinker. Then, after Operation REVIVAL, a new request came up the chain to the design teams:
"Survivability onion theory is A PACK OF STUPID LIES. BLINDLY SLAP MORE ARMOR ON MY MECH RIGHT NOW YOU BOUNDING STRAVAGS!"
The Hellbringer would be the fancy gadget design that mates advanced technology and dubious assumptions as though the very ghost of Robert McNamara were consulted for the project, while the Ebon Jaguar would be the return-to-basics design.