I agree with what you're saying though I'm more supportive of Nitara's return than you are, because I think there is quite a bit of potential for her.

Another good idea would be to bring back Sektor. I know its difficult to design missles in 3D for him, but it would be interesting to find out what happened to him in terms of his storyline, instead of just hearing it from second hand accounts like handheld devices.

YES: Rain, Reiko, Sheeva, Stryker, Frost, Blaze, Fujin
NO: Motaro, Mavado, Hsu Hao, Nitara, Kai, Mokap

Stryker, Mavado, Nitara and Kai are some of my favourites, and all high up on my wish list for comebacks. These are, imo, four of the most underrated fighters in the series, and to me, far more interesting than many of the regulars, both in gameplay and storyline.

Mavado has too much involvement with other characters to not make it back at least one more game. Kai's caperoia was akward in MK4/MKG, but if the 3 style system is kept, this could work very well as one of his styles. I'd love to see more of Nitara, one of my favourite female characters, and she should make more use of her vampire abilities in fights. I'm not going to expect Stryker since so many other fans hate him, but never say never. Nightwolf was almost as despised by the fans in MK3 etc, and he made a comeback, so Stryker could too.

I think Fujin also has a very good shot at making it to MK7. To me, he was kindan boring, but there's a lot of untapped potential in a fighter with wind based powers. Plus with the Dark Raiden storyline, he could fill the role as the sane god, and the heroes mentor.

I would also be interested to see Frost and Sheeva come back. Frost desperately needs some unique moves. She had a potentially interesting storyline and cool look, but gameplay wise, was Sub Zero with boobs. Sheeva wasn't that interesting, but I think they could turn her into a great grappler character, as MKD was badly lacking in powerhouse fighters. Besides, why should Goro be the only Shokan to keep returning?

Certain characters are, imo, best left as one hit wonders. I actually like both Jarek and Hsu Hao, but both of these guys have served their purposes, there's nothing more they can really do. Same with Rain, though I was never really into him. Tanya should have also stayed a one hit wonder.

It's highly unlikely we'll ever see them again, but just for the record, Reiko and Mokap should be left to rot in the MK graveyard forever. Same with Shinnok and Motaro. Really couldn't care less about Blaze either way.

Rain:

Like I said, all disserve second chance, but he needs a LOT of improvement, so I say bring back others with more potential.

Reiko:

Huge potential, specially with the entire Kahn conflict (even if he is not Kahn)

Motaro:

They should try to give Sub-Bosses a decent storyline. Goro has an excellent storyline, his is decent, I say bring him back, NOT as a sub-boss.

Sheeva:

Definitely! She has so much to give!

Mavado:

Well, know that we have like 8000 black dragons we need the red dragons.

Hsu Hao:

Hmmm....same as Rain.

Nitara:

This is probably one of the few characters that can create huge twists in the storyline. She has huge potential.

Stryker:

YES! Im no fan, nor do I miss him, but Im really sure he can do so much if given the chance. Just stay away from the cop crap and any possible involvement with the SF.

Kai:

Why not? He has potential, but I rather see other more important/needed characters.

Frost:

Definitely. If you don’t want 2 ice ninjas, make Sub-Zero rest a game and put her in his place. She can do so much! Possible alignments with evil or traitors to control the Lin Kei such as Sareena, Quan Chi, the red dragon, etc.

Blaze:

Not now. He does have an interesting story...but nothing deep or that important, plus he is very unoriginal (his look). Same as Rain and Hsu Hao.

mavado: he and kabal cant just stop there

hsu hao aka mr. slave: i am positive he will not return

frost: people would rather see frost return than sub zero?

rain: no potiential.... someone explain his great potiential

nitara: i think shes more intresting then some.

People they should bring back-
Nitara
Mavado
Kano
Jerrek
Sareena
Shao Kahn
Cyrax
Smoke
Sektor
Sub-Zero
Mileena
Kitana
Sindel
Tanya
Nightwolf
Ashrah
Frost
Rieko
Jade
Sonya Blade
Jax Briggs
Raiden

People they shouldn't bring back-
Everyoine who wasn't on the list above

^I said one-shot characters, characters who have only been in one game, a good part of those are reoccuring characters.

Rain
I'd like to see Rain get a second chance. I think with everything that's going on with Edenia and Kitana this owuld be a good time for him to re-emerge and I think he could play an interesting role. Personally I'd like to see him trying to win Kitana's approval/affection, but there are plenty of directions he could go.

Reiko
Reiko's always been a favorite, and there's a part of me that wants him to get a second chance....but I very much doubt they'll do anything good with him. They'd probably turn him into yet another Shao Kahn lackey, but in my dream fantasy world, he'd come back all bad ass with his own purpose and connected to Sareena like he should've been.

Motaro
No real interest in Motaro. Poorly developed and he's dead now. I know "no one really dies in Mortal Kombat," but I'd rather they don't bother trying to exlpain how and why he's back. That said though, since it appears the Shao Kahn no longer favors the Centaurs and the Shokan are enemies of Edenia now, it could be interesting if a new Centaur character popped up.

Sheeva
Same as Motaro. Frankly, I'd rather Kintaro (another One-Shot) come back, who at least hasn't yet been confirmed dead.

Mavado
I liked Mavado and the Red Dragon seemed cool. He'd be easier to bring back than Motaro of Sheeva and I'd like to see how he deals with Kabal's new Black Dragon and what happens when the Tekunin makes it's move. MK:DA also sort of hinted he was a greater threat to Sonya than Kano, which I would've been interested in seeing be developed.

Hsu Hao
Nah, leave him dead. He's served his purpose, he was very bland IMO, and I'd rather see other Red Dragon members.

Nitara
I liked Nitara. She seemed cool and I think her story can go in some interesting directions. I've no real concrete ideas myself, but she can still go places.

Stryker
Meh. I can't say I don't want him to get a second chance, but he's at the bottem of my list.

Kai
Pretty much the same deal with Stryker, only I'm slightly more interested in Kai.

Frost
I think we'll see Frost again, whether she's "hibernating" or her soul decended to the Netherealm. I'd like to see her past be developed, and then ally with Noob Saibot, and perhaps have a rivalry with Sareena.

Blaze
See Kai and Stryker.

Fujin
Fujin's not one of my favorites, but he does have potential and he could definitely play an interesting role with Raiden going dark now.

Another One-Shot I'd like to see: Shinnok
Like Fujin, with Raiden going dark and the One Being emerging as a real threat, I'd love to see what role Shinnok could play there.

Also wouldn't mind seeing Kia and/or Jataaka pop up again. What the hell. They could come back for revenge against Sareena and Ashrah and side with Quan Chi or Noob Saibot or both.

Rain: I think Rain should stay dead. We already have a ton of ninjas we don't need any more ninjas... and his character seemed kinda bland.

Reiko: Reiko was a mistake and he caused that whole Reiko=Kahn Fiasco
HE DOES NOT RETURN

Motaro: Eh, I don't see much purpose in bringing Motaro back, the fans didn't like him and plot wise he wasn't all that interesting.

Sheeva: Personally, Sheeva might be interesting to see from again. I didn't really find nightwolf all that interesting from MK3 but they did a good job of making him in Deception, and I bet they could do the same with Sheeva

Mavado: Yeah, he could make a return. It would be foolish to open up this whole plot link to the red dragon and then just close it.

Hsu Hao: Naw, Mavado is enough to represent the Red Dragon

Nitara: I dunno, this is a tough one, but she has potential.

Stryker: No.

Kai: Hmm. Kai didn't really have much meat to him but its not necessarily a bad idea

Frost: Definetely. Seeing Frost's return is a good idea. She really had a great dynamic with Sub-Zero.

Blaze: Of course. Some of the greatest Mk Characters come from obscurities from past games (Ermac o.o)

Fujin: Yeah he should be in it. Since Raiden has went AWOL, I can see him returning.

I think I forgot one...

Khameleon: Yes, she should if she is to add to Reptile's story... Reptile needs more depth now that he's a just a dog for Kahn... (or was anyway)