It's still worth it to do the SCJP. Maybe there will be changes in the exams in the future, but nobody knows right now. This is what Oracle has said about it:
What are Oracle's plans for Sun's Certification Programs?
Sun certification has long been recognized in the industry for endorsing the competency, dedication, and motivation of leading IT professionals. Today, more than 650,000 certifications have been granted worldwide. Oracle plans to increase investment in Java, Sparc, Solaris, and MySQL technologies which is expected to increase the demand for professionals with proven expertise in these areas. Oracle remains fully committed to developing and promoting the expertise of these sought-after specialists. Oracle University will continue to provide comprehensive training and certification programs for these areas, and will honor all unexpired certification exam vouchers purchased through Sun.