This thread is based on fundamental flaws that anybody who paid attention to the stats and discussion would recognize in a heartbeat.
ALL EBB4.5s have 7 support slots, the same as a regular BB4, ALL EBB4.5s are slower than their respective BB4s, and most are slower than the associated BB5s as well. This is to compensate for having BB5 guns, and to keep them inferior to proper BB5s.
By comparison, ALL EBB4s are just slightly buffed (extra ammo, more DP) BB4s with an extra support slot. EBB4s were designed to help leveling by both breaking up a long grind (14 levels - experience penalties kick in after 10 levels above the ship) and allowing more sailors to be leveled at once.
For everyday play (GB), and leveling, EBB4s are better. However, in World at War, as well as organized team play such as HA or fleet wars, I'd choose the extra range of EBB4.5s over the extra speed and support slot in almost every case.