155 watts does not go out of the BHSE chassis, as you inaccurately claim (whatever that means anyway, as "watts" are a measurement of power and not thermal energy or temperature). Some of the power the BHSE pulls from the wall goes directly towards driving the headphones. But of course not every amp is 100% efficient so some of that power has to be released as heat.
A larger chassis would achieve absolutely nothing except make the amp heavier and bigger. More internal space would help what exactly? You failed to note in your post that the BHSE amp and power supply are both completely ventilated on both their top and bottom panels, and that the amp has two large heatsinks, one on each side. If the amp wasn't ventilated, of course it would make sense for a larger chassis to have been used, but it's completely ventilated, so your point is moot. The fact that the amp does get hot means nothing - the entire chassis is designed to allow complete dissipation of the heat and the parts that get hot are all thick aluminum. Also, while you might think the amp gets "exceedingly hot," I'm sure that Justin thoroughly tested the amp for 100% reliability before he started putting down the finishing touches on the prototype, because what sort of amp designer wouldn't? (Mikhail at Singlepower aside, of course.)
Given these amps are Class A, it is not inappropriate to speak of their total power draw as heat output. I'd be willing to wager that both amps are about 10% efficient There is no problem using watts when speaking of heat output from electronics - it is common practice, and almost never do you hear about the heat output of electronics in the form of calories, joules, or btu's.
I also don't think I said a larger volume chassis would make a difference - if I did, I apologize. What I meant to say (and am pretty sure I did say) was that the WES definitely remains a LOT cooler, and this is possibly due to the fact that it has a more MASSIVE chassis. More aluminum will indeed be a more affective heatsink. Surely you know that?
I am well aware of what holes are, and what heatsink fins look like Also, only a nincompoop would think that a case would not be designed to dissipate heat.... However, complete ventilation does not equate to effective cooling, when such large quantities of heat are produced! Natural convection seems to be not enough to cool the BHSE to the same degree as the WES. Note that I also never mentioned that the BHSE got TOO hot, nor did I mention its heat was in any way dangerous! I simply noted that the amp got hot.
The fact of the matter is, I have TOUCHED these amps after a few hours of use. The BHSE was very unpleasant to the touch, the Woo was barely warm. I am not claiming to do this from a strictly theoretical perspective. Nor I am not bashing any designers. They simply have different temperatures - it seems an odd subject for debate