A few points:

(1) I strongly agree with Ralphs points. The more we include the harder to
guarantee standard behaviour within servers.

(1) Terms should be quoted, when no confusion is possible quotes may be
ommited.

(2) Why is relevance a relational operator?
For me it is a sort of the result set. If sorting is important just add it.

(4)  Are the following the same?
1: nobath.all="zing for you"
2: nobath.all="zing" "for" "you"

(5) Do we really want:
"nobath"."all" relevance zing!1"for"-you

I would prefer:
1: nobath.all="zing" w "for-you"
(the server knows what he did during indexing "for you" or "foryou" )

Which is maybe interpreted as:
1: nobath.all="zing" w "for" w "you"
2: nobath.all="zing" w ("for" and "you")

(6) ?6 is cute as wildcard but ?????? generates less problems.
nobath.isbd=1234?5678

(7) Is it wise to include an escape for the wildcards?
This would allow
nobath.isbd="1234?5678"
nobath.wholetitle="the lazy * jumps over the quick *".

now I think the syntax is:
nobath.isbd="1234"?"5678"

(8) Are these the same?
1: nobath.whole = "tasmanian tiger" and "siberian tiger"
2: nobath.whole = "tasmanian tiger" and nobath.whole = "siberian tiger"

Rob