Ratha Yatra is a festival of ecstasy because Lord Caitanya knew very well that Krsna cannot be happy outside of Vrndavana. Vrndavana is the place where He belongs! Vrndavana is the place where everything is designed for Krsna, and therefore Krsna can only be happy in Vrndavana. So Krsna had to be brought back to Vrndavana.
How could Krsna be in Dwarka? That is not the place where Krsna is at home. In Dwarka, Krsna is in separation. In Dwarka, Krsna can never be satisfied. Dwarka is so opulent t