TATA preponed launch only to place a doubt among potential new car buyers in Indian market. They got attention midst of a new i20/Polo/Punto/Mobilio. Its a good strategy IMO, customers were anyways going for a non TATA car, if they manage to grasp even 20% of them then its a good move.
There is sufficient marketing done for the Zest IMO like placing it in Malls, IT parks. Now with the new Polo, Punto, Elite i20 and the upcoming Ka(New Figo) in the market TML should be very cautious since they don't have a good name in the industry.
Since the product is very good, somehow we(I take the liberty of saying WE ) don't want it to fail. If this doesn't set the sales chart on fire then nothing can change their fate.
Lets wait and watch .