Is that because certain ships have fleet commander system (extra equipment/weight)? It was speculated that 055 will be the flagships of China's several fleets.
Let me explain this a little bit clearer.
You can see the office rank chart here:
You see, O-5 is a commander, O-6 is a captain. O-7 and above, you can call yourself an admiral. The CO of a destroyer must be a commander; if he wants to go higher, he needs to go through captain, and then become an admiral. How? A captain will not appear in thin air. The only two designation for a captain in Navy is the CO of a CVN or CG; and there are not much ships for them. If US Navy lose all of its cruisers, the promotion path for a commander would be very narrow: they will compete with other 90+ commanders for only 10 CVN CO slots, and that's a long shot. However, right now with 22 CGs still active in duty, the captain slots would be 32, that's generally 1 in 3, and much better chance. So the whole navy bureaucracy knows that, and that's why they are struggling to keep CGs active. It's not about how Ticonderoga is better than Burke; its about the Navy office rank would be in proportion and healthy.