In watching tonight's season premiere of Top Chef Masters , the haute cuisine culinary competition series that spun out of Top Chef a few seasons back, it's easy to get a sense of what's been lost rather than what's been gained by the format changes. (The latter can be summed up in two words: Ruth Reichl.) Gone is Kelly Choi, she of the perfectly coiffed mane. Gone is the complicated but novel star-based ratings system. Gone are the early heats. What remains is rather like Top Chef . Or exactly like Top Chef , in fact, save for the experience of the master chefs competing here and the fact that their winnings go to the charities of their choice rather than into bankrolling a restaurant. Choi has been replaced by suddenly ubiquitous Aussie chef Curtis Stone, yanked onto the cable channel while still appearing on NBC's America's Next Great Restaurant . He's affable enough but his omnipresence--from here and the NBC show to commercials--is a bit off-putting, i