Ok so after all this wand talk, I went and tested it on my disc priest. Please note that results will vary vastly depending on your spec's artifact traits.
99 disc with 14 trait artifact weap (742 ilvl) verse 6/6 wand with 731 ilvl.
ALL NUMBERS ARE INSIDE BG WITH PVP TEMPLATES ACTIVE
1st value = artifact, 2nd = wand.
HP 262 k / 250 k
mana 155k / 155k
int 3239 / 3400
stam 4368 / 3998
armor 531 / 559
crit 10 / 10
haste 6 / 6
mastery 16 / 16
vers 6 / 7
TOOLTIPS;
penance(dmg) 25 804 / 22056 (artifact has +12% damage trait)
shadowmend 28420 / 27205 (artifact has +10% healing trait but it still scales very well with wand int / vers)
smite 7844 / 6529 (artifact has +15% dmg trait)
SW pain 15607 / 13028 (artifact has +15% dmg trait)
PW shield 18946 / 19950 (artifact has +15% absorb trait but obviously it scales better with wand int / vers)
PW solace 10 459 / 8706
clarity of will 31004 / 32646
Conclusion; Raw Intellect goes up by 161, less than a greater int flask. PW shield and clarity absorb goes up slightly, everything else goes down slightly or stays the same. This means that you can use a wand to try out other specs without completely gimping yourself
I'm pretty sure I could shadow / holy in bgs with a wand and perform on twinkish levels.
Going to do this same test on a 99 frost mage soon!