This risk can be hedged by shorting ETH then using a portion of the resulting ETH from splitting to repay the loan. You end up with 8% more ETH than when you started. While ETH may drop in value, as long as ETH has >0 value at the end you come out ahead, not factoring in trading and borrowing costs. (Current ETH loan rates on Poloniex are 0.01% per day so that is fairly low.) Although even then you can short enough ETH to hedge the extra 8% too and lock in a price on the profit.

The other issue is that security problems with The DAO design (both identified and potentially unidentified) mean you can't be completely certain that splitting off to retrieve ETH will work properly.