Considering the exceedingly impressive degree of corruption revealed in top ranks of the PLA, it would be truly unbelievable if PLA's acquisition is not also influenced to a impressive degree by political considerations of pleasing non-professional fan boys in the power structure of the government and amongst the uninformed public.
I guess this answers the question that why even question the need for 055 to begin with.
Lack of technology especially in propulsion fields. And doctrinal constraints, with a focus on near-shore/brown water operations.
The breakthrough of China's marine gas-turbine technology was probably a bigger revolution than the J-20.
052D is a very good modern destroyer, but its potential for upgrades have been tapped out. It has crammed a 64-cell VLS, by far the most in its weight class. There is no room for additional CC facility and staffs, bigger and better senors, future armament like EM railgun and direct-energy weapons. The speed and endurance are also not ideal for global blue-water navy as envisioned by the PRC leadership (and needed).
The 055 is not some prestige and vanity project; it was even conceived back in the '70s. But China has been challenged by the technologies needed to build such a ship. It's been a multi-decade journey to get to this point where PLAN can finally realize its dream. As documented by Jeff, the evolutionary history of various 052/052B/052C/052D is a testament of such endeavor.
It's pretty understandable and reasonable to discuss/debate/speculate the role of 055 and composition of future PLAN destroyer fleet. But I believe 055 will be the backbone and primary battleships for PLAN blue-water fleet, not 052D. 052D is and will continue to be built in significant numbers where construction of 055 ramps up, which is going to take some years. Besides, 055 will definitely go through multiple iterations and upgrades, and eventually will eclipse 052D as the backbone of destroyer fleet in blue-water.