Stalkers helm
12 stam
31 agi
8 int
3 sockets for 96 ap(if you spend alot of gold)
60 ap
4 MP5(yay)
Swift arrow helm
69 stam
46 agi
46 int
45 crit
95 ap
46 res(who cares)
so the UPGRADE from stalkers is 57 stam, 15 agi, 38 int(alot of mana), 31 AP(assuming careful aim), 45 crit.
This is a significant upgrade for less than the cost of the gems.
Plus you don't look like an idiot. The stalkers helm does not compare to S3 which was best in slot in many ways BC.
Note the conditional - if you are PUGGING. If you have a good guild to run with you will clear heroics. If you PUG with that gear you will not get many invites.
T5/6 and BT/sunwell was not replaced easily pre-heroics anything else should be gone by level 78.