Conditional Clearance..
If there is traffic below the arriving aircraft (or a VFR route controlled by another sector) or any other reason to keep the arriving aircraft above the initial approach alt for the approach, for a period of time or distance, then:
The use of a conditional clearance would appear to be appropriate;
XXX turn right heading 330, cleared ILS approach Rwy 36, leave 2500' on the GlideSlope.
This way, the clearance is issued, and the condition is to (effectively) maintain (or decend to) 2500', with further decent on the Glide...
I understand the issue of receiving a "insinuated" clearance, but the problem is clearance limit, and without a clear instruction, there is a risk of confusion in the event of a radio failure.