The eisenfaust is definitely the obvious target in that situation, due to fairly high firepower and low survivability, and that's why it's so weak. The rest of your lance might be "thanking" the eisenfaust, but it won't be for very long. The thing about assault mechs is that it takes a *lot* more effort trying to "silence those guns" and you'll have both the eisenfaust *and* the Thunderhawk firing at you for the full duration.
However, I think this little guy has some strengths that are overlooked in the article. What happens when you pack 30 DHS on a mech with such a low rated engine? If you said, "crit-packed little MFer" you won a gold star! The Eisenfaust's heat sinks actually increase its combat durability, because when you get a crit you're more likely to hit a DHS more than anything else, and it *is* heat efficient enough that losing DHS doesn't impact it's combat effectiveness that much. Combined with a lack of explosive ammo, the XL engine, though still a liability, is not as much of a liability as it is on similar designs.
Also, this guy is almost the poster boy for "why BV2 is great." Without a balancing system, it is definitely lackluster, but if you are using BV2 it is *cheap* for the firepower it brings, which definitely makes it worth using as a body guard, despite its crippling vulnerability.