The 1960s/1970s Sea-based Anti-Ballastic Missile Intercept System (SABMIS) had their phased array radar split between the forward and aft part of the ship. TICONDEROGA cruisers were similar in their AN/SPY-1 was split 2 arrays forward and 2 aft, as did the proposed Guided Missile Cruiser Baseline and Strike Cruiser.
With the introduction of the BURKE-class, all the arrays are concentrated. A proposed ABM version of SAN ANTONIO (LPD-17) shows all the arrays concentrated forward, as well.
It appears the USN decided it as no longer worth the price to prevent a single hit from potentially mission-killing the ship. I suppose a single hit might do enough damage so that even those arrays are left intact they would still be inoperable due to other damage.
Does anyone have any documentation that explains the change?