Nice, that one has been bugging me for a long time (but never enough to do anything about it). However, why not SV_LinkEdict (ent, ent->v.movetype != MOVETYPE_NOCLIP)? A good compiler will do the same thing (I've seen gcc do it), but I feel the one call is clearer than two separate calls. Can even do SV_LinkEdict (ent, !developer.value || ent->v.movetype != MOVETYPE_NOCLIP).
I think this is one of those things that id never fixed due to lack of time and pressing need, rather than intended design.
ps, I prefer to use "if" to select different code paths rather than simple parameter values (unless things start getting too messy, then I'll use an "if"). Also, if you prefer to keep the ==, use !(ent->v.movetype == MOVETYPE_NOCLIP).