A state-endorsed plan to give Carlsbad's Batiquitos Lagoon a $15-million face lift was rejected as "totally unacceptable" by two developers who own large portions of the coastal wetland. Representatives of Hunt Properties Inc. and Sammis Properties said the plan would neither work nor create a visually pleasing setting at the lagoon. At a meeting with government officials, the developers advocated an alternative approach devised by their consultants--and rejected by the state as inhospitable to birds. State officials said that without the developers' support, their proposal to revitalize Batiquitos by dredging it and restoring regular tidal exchange with the ocean could be doomed. Also at risk because of the apparent stalemate is about $15 million that the Port of Los Angeles has offered to provide for the lagoon project.