BHM runway 18 close-in obstacle environment precludes an ILS.
Looking at charts I have available, it seems that the segment after BASKN (IBXO 6d @ 2300ft) is 3.3deg to a threshold (IBXO 1.3d @ 644ft) with PAPI's set to 3.2 degrees. It would therefore seem that the obstacle clearance issues are outside of IBXO 6d.
I have never flown into (this) Birmingham before but remember well a very similar approach that I used to fly regularly into Stuttgart, Germany before the runway was lengthened eastwards.
In those days (I'm talking early 1990's), likewise the terrain to the west precluded a 'normal' ILS and one carried out an NDB/DME procedure. The Germans had, however, installed a full 3 degree ILS which was promulgated as 'not for navigational use', but it did provide for a very useful cross check and help SA enormously when flying the NDB.
Surely, without bulldozing land, a 3.3 degree ILS could be installed, even if not for operational use?