Again, let's say that the Wizard has a... +15 Init Mod. If you roll a 6 or higher, you go first. Period. The ONLY thing stopping that is Celerity. If you pick up Nerveskitter, then you go first, period.
Unless the Ring of Anticipation is *really* cheap (like <3kgp cheap), I'd consider going with something else, instead.
Another thing to consider is the Enemy Spirit Pouch (keyed to Arcansists). If you DM allows it, then it's 2100 gold for a +3 bonus on attack rolls against arcanists (on top of other stuff). It's a really cheap static boost to numbers.
Shadow Creature was updated in Lords of Madness, and I have to agree that Gravetouched Ghoul will serve your purposes better. Switch Intelligence and Charisma (GGhoul gives +2, so your Int mod actually stays the same) and play up Charisma a little more. Drop Telling Blow, Weapon Focus, Power Critical, Improved Critical, and Spring Attack in favor of Darkstalker, Power Attack, Divine Might, Elusive Target, and Death Blow. 3 levels of Lurking Terror will improve the save on your paralyzing attacks to 10 + 7 (Cha) + 7 (1/2 HD) + 3 = 27 (30 w/ +6 item), which is actually really tough for even high-level characters to shrug off when it's hitting them 3 times each round.
Also, the luck bonus to saving throws isn't that hot, relative to Gravetouched Ghoul. Gravetouched Ghoul gives a +2 bonus to Reflex and Will saves from ability boosts, and makes you immune to almost everything that hits Fort. You can stack that with a Luckblade, Luckstone, Recitation, or, dare I say, the Ilyyukur's Mantle spell in Unapproachable East.