I can’t say I’m sorry to see so many seriously bad old-time restaurants dying on Columbus and Amsterdam lately, but it is a little disheartening to see that so many of their glitzy replacements are all following the latest food merger from hell. I call it Glasian — with the first two letters, of course, coming from Gloppy. At a time when Americans are becoming so much more sophisticated about nuances among ethnic cuisines, what’s with this herd instinct to turn out one menu under Thai, tempura, Vietnamese and sushi? It almost makes you long for the good old days when the ubiquitous mixed marriage was China-Criolla. At least that had historical precedent.