It is completely accetable to bind parity (RAID5, 3, 6) and non-parity (RAID1, 1/0) across buses and enclosures. In fact binding RAID groups across two enclosures in separate buses will help with rebuild times. This is discussed in the document titled EMC CLARiiON Best Practices For Fibre Channel Storage. You can find this document in the documents section of this forum.  So if it doesn't bother you that your RAID 5 ggroup is split between enclosures then don't change it. There really is no need to.
We have a RAID 5 (4+1) RAID Group with two LUNs that spans two DAEs and Bus.  Two in 0_3 (0_3_13, 0_3_14) and three 1_3 (1_3_0, 1_3_1, 1_3_2).  After closer inspection on 1_3 we have a hot spare which I can relocate and an empty slot but the slots are not adjacent to each other.  The three are at 0,1,3 and the would be available slots would be at 13,14.   The LUNs will house Exchange DBs, so should I destroy the current RAID group which spans two DAEs and Bus and recreate the RAID group on one DAE but the disks aren't adjacent to each other?  Thanks.
Multiple DAE provsioning question