If I knew we'd be horrible for a decade after the championship, yeah I'm pretty sure I'd do it. And if I knew we were going to win a championship but might be horrible for a decade, I'd definitely do it.
And if I believed Durant was going to stay healthy often enough to lead us to a championship, regardless of what shape we'd be in afterwards, I'd do it. But the question marks surrounding Durant's health (plus the CP3 injury risks) alter the equation for me. At that point, not protecting the picks outweighs the improved odds Durant's acquisition gives us, IMO.