I agree that Angle was a bigger impact to TNA, due to him being a active wrestler still. But I don't think Angle was ever over with fans as much as Foley once was. Sure Foley isn't as over as he once was, but he's still a bigger name then Angle ever was, so I think he could bring more hype/ratings at first, if TNA builds this up right.
The main reason why Foley seems like a over the hill has-been is because thats how Vince has made him look over the last few years. It's pretty obvious HHH/Vince have buried Foley in recent years. Foley has said he wanted to wrestle the last two WrestleMania, and was not given at match. He's came up with storylines/ideas and they were all rejected. Brian Gerwitz(who was a believer in Foley still) even came up with storylines for Foley last year and they also were rejected. Think about it after SummerSlam 06, Foley kissed Vince ass, it was suppose to lead to a match with Vince and a push for Melina. What happen nothing? Foley is then a throw in a Vengeance- Night of Champs main event. What happens? A week before the PPV, Foley/Umaga are suppose to have a match to hype the PPV. What happens is they brawl before they get in the ring, and Umaga destroys him. Now if your ordering this PPV, what chances do you think Foley has at winning, if you see him get destroyed by another guy in the match? Then of course Foley jobs and gets pinned by Cena. After that Foley wrestles the The Coach in a two minute match on Smackdown, and tags up with Hornswoggle against the Highlanders to get into the Royal Rumble(in which HHH gets him out). I can't see any better example of being buried.Now Foley starts calling Smackdown, and Vince treats him like his bitch. Seriously does Vince realize what this guy has done for your company over the years? I know there realtionship has been very hot and cold the last 7-8 years, but thats just BS.
Not to mention even before Vince buried Foley, his storylines were very boring. Foley played the old great wrestler, trying to prove he still has it against a young guy, and always would lose. It was pretty cool against Randy Orton, but got pretty old after that. If Foley is going to work in TNA, they just need to bring back the Foley that was a success. He needs to be the 90-00 Foley, and no mention of him being old or how good he use to be. He just needs to be the fun loving guy, who will kick ass and get his ass kicked trying, and he also needs to win some matches to keep things interesting. In all honestly Foley isn't that old he's only 43, and a few years older then many of the WWE main eventers. Sure his body is beat up and he can't wrestle full-time anymore. But I think he will still wrestle 6-7 matches a year(thats what he did in 06), as long as he doesn't have a major injury. If Foley gets himself in decent shape, he can still put on quality matches , he just hasn't been given the chance to do that in WWE since 06. If Vince wasn't a cock I think Foley would have been happy wrestling a few more matches, and just do stuff for the WWE and retire for good. But going to TNA is gonna make him wanna wrestle more and do what it takes to make their show better. Only time will tell the impact this will make on TNA, but Foley probably the biggest star to ever be in TNA(next to probably Sting), so it has to worry Vince some, and if it didn't I don't think Vince would have paid Foley big money to stay three years ago. As for Foley contract it seems like Spike TV helped pay part of Foley deal(so they must think he will bring in a good amount of ratings), in which Foley would agree to do TV work with their network as well. So it does seem like Foley will get a decent amount of money to go to TNA after all.