You didn't seriously think they were going to scrap a design and make another one because you don't like it do you.
Of course not. I commented, because I want to hear Simon's explanation about his company's choice of making a 250W chip, in order to determine how risky an investment in Hashfast would be.
The company believes they have the expertise to design a large efficient processor. If they can there is no reason to use a larger number of less powerful chips. The less integration at the chip level the more integration that is needed at the board level. More wafer cutting, more chip packaging, more complex boards, more supporting components, more fans, more heatsinks, more assembly, etc. A larger number of smaller chips gives you more flexibility and makes cooling less of a challenge but the system isn't going to be cheaper or more importantly assembled faster.
"More wafer cutting, more chip packaging": true, but negligible. A Baby Jet costs $5600. At most, a few extra dollars would be spent to slice and package 4 chips instead of 1 per machine.
"more complex boards, more supporting components": true, but completely negligible. Look at Avalon: each additional chip on a hash unit has merely 13 supporting components (resistors and ferrite beads, all 0402) which cost at most a few cents. An extra bitcoin mining chip added to a circuit in general does not need much supporting components because all it needs is power and a low speed serial i/o line.
"more fans, more heatsinks": false. As you pointed out it's a curve. It's a choice between more heatsink + fewer fans, or less heatsink + more fans. But both solutions, air and water, must be designed to cool 250W regardless.
"more assembly": false. The little extra time of pick-and-placing, say 3 extra bga chips, is completely negligible compared to the extra assembly time required to install the water cooling system. I guess Hashfast could save time by shipping systems with the water cooling completely untested and unassembled. But still, the extra time to pick-and-place 3 extra bga chips on a board with 100+ components remains negligible.
Air cooling is cheaper and faster to assemble. Nobody argues against that. I am surprised that you do(!)