I think I liked this one a lot less than you did, not the least of which because they relegated Alex to the last twenty minutes. That made it seem more like a stunt than an honest-to-goodness plot device. The best part about the episode was the old Alex As Prosecutor: she was back in her element, and you could see her relishing in it, even though she was a witness.

That leads to another point: yes, Casey definitely could not have gotten away with, in a cross, what Alex was able to get away with on the stand. I thought it was brilliant, but it ended up making Casey look dumb. I don't understand why TPTB are writing her as so... I can't come up with a good adjective, but she isn't up to snuff as an ADA. Having Alex back compounded that perception (of mine).

I was spoiled, but I still didn't recognize Sandoval at first. I saw no reason for him to be in this episode, as easy on the eyes as he is. Although I realize that he asked to stay on the case, everything he did could have easily been handled by Benson or Stabler. Hell, Munch and Fin, too. Wouldn't it have been nice to see their reactions about Alex being alive?

I did perk up about the hitman being part of the IRA. Probably un-PC of me, but some of those guys are SO brutal. However, alluding to the title, and how he was supposed to be a 'ghost', so good at his 'job'... yet when the detectives storm his hidey-hole, he... runs right out where they can see him? I dunno; I'd think an IRA hitman who can walk through walls would have a better, more secretive escape route. That he didn't made me laugh.

I found the scene by the window in the hotel room (although I was thinking, "Um, curtains! Hit people will be able to see her!") nice, and true to Alex's character; sadness, but no tears. I also liked that they kept in Alex and Elliot's backgammon game.

A good SVU episode is one that's very tense-- we know they do those kinds SO well. This one wasn't very thought-provoking, nor was it tense. I didn't expect them to bump off Alex or the boy. I can't say that I can come up with a better idea for The Return of An Old Friend, but I didn't like what TPTB came up with, either.

Some shallow thoughts:
Elliot got hit in the belly with a board!

Sandoval's Visual Aids Scene: so unhelpful. I actually thought it was a little demeaning, as if our detectives can't figure out things without ketchup bottles and salt. Heh.

***

I do think next week's going to have major de-Stablerization. I think I'm going to be cringing whenever Stabler gets in Matthew Modine's face, waiting for the blow to fall. An interesting aside: while watching last night's ep, OD (who was thrilled that Alex was coming back) commented on how up-in-his-face Stabler was getting with the IRA guy. "Oh, he's gonna hit him!" Even the young fans have caught onto Stabler's explosiveness.

I totally forgot to comment on Casey and what she pulled in the courtroom. That wasn't bad-- it took balls and initiative. What I couldn't stand was her comment to Benson and Stabler later: "You hung me out to dry". Uh, wtf??? They couldn't say a damn thing or do anything but re-arrest the guy, and yet she blamed them for what she initiated?? Ugh.

I forget Casey's background, but I believe she was only trying white collar crimes previously. But she has had some time. Still, not every single prosecutor is brilliant! Though in fairness everyone was on Benson & Stabler's backs for perjuring about Alex. Casey had no way to know Alex was still alive; if the court had found she did she could face discipline, so I can understand her outburst.

You're right; the treatment with the IRA guy was kinda weak. Didn't think he lived up to his reputation, either; not very menacing or threatening looking/acting but more like a working class Irish bloke.

I liked the episode because it was nostalgic; the human component of the folks involved made it very poignant to me despite the lack of mystery or twists, which I can do without from time to time if other things make up for it. It was thought-provoking on my end because of the position that Alex (or any other victim like her) has had to be in. That we don't get very often, and it shows the side of the witness protection that's rarely explored or thought about, if at all.

Matthew Modine freaked me out in the preview. A very ewww character. Not really looking forward to de-Stablerization at all.