As for Garrett, I think he was great. Could someone else have done better?...who knows and I guess we never will. I think he did a wonderful job of being the flawed hero.
I think there are numerous other actors who could've done better. Personally I think they should've had Elijah Wood do it (and this was before he had his role in Tron: Uprising).
Garrett wasn't terrible, but his wooden acting took me out of it. For example, I don't know about you, but I would've lost my shit or freaked out a little. He didn't seem at all mystified or emotional about the fact that he's in the crazy computer world. Even the scene when he first meets his dad again didn't feel natural.
Just compare Bridges' performance with Garrett's as the "fish out of water human" and you'll see what I mean.
I still thought Bridges was incredibly wooden and contrived-seeming. The whole reunion scene confused the hell out of me, but I feel like much of that was the writing. I know, it's a fine line to walk between "what would be authentic for two people who haven't seen each other for 20 years" and "getting lost in mushiness can we just get on with the movie," but...
I definitely expected more emotion from Bridges than from Hedlund. To Sam, he's reuniting with a dude who, as far as he knows, walked out on him when he was a little kid. At that point, Sam has no idea that his dad didn't stay by choice. I'd be pretty chilly too if I was meeting up with a dude who I thought abandoned me as a child to hang out in a computer world with some chick. But Bridges disappointed the hell out of me. Flynn's seeing his one remaining family member, someone he hasn't seen for 20 years, his own son who he's probably missed like crazy, he's seeing his child all grown up, etc. I would think he'd grab Sam and never let go. He starts out okay-- incredulous, tears in his eyes. Then it's like he switches off, and he's like "well, I'll go away and we'll talk later." Hell, Hedlund's doing a lot better job in that scene-- he's got this quizzical look on his face and tears in his eyes, like "my dad was just happy to see me and now he's walking away?" I probably had a similar "wtf??" look on my face as I watched.
I'm willing to give all of the actors except Bridges a bit of a pass for the writing; there's only so much you can do with lines that the writers haven't built to their full potential.* But I hear Bridges did a lot of building of his own character and writing Flynn's lines, and yeah... he just didn't do it for me, except for in a couple scenes when I finally felt there was something *real* about the character.
*Look, I'll try to be fair about it. A screenplay's got to be a bitch to write-- you have to get your entire plot into a specified time span, and no matter how emotional, the plot still has to MOVE. I understand that something has to be sacrificed in the interest of expediency; it's not like writing a story where you can take all the damn time in the world if you want to get character feelings and reactions authentic. I'll even say that for all we know, the writers did a great job and someone else came back later and was like "oh hell no,it's way too long, you need to cut a lot of shit out" and they did the best they could and this was what they were left with.
But the script and events of the film itself left a lot to be desired for me. But again, pretty much everything that makes me unhappy about it is something that I can understand couldn't really be dragged out. I think it was a lot of story for the time limit they had to work with, and I think they wrote themselves into a lot of corners that way. If it was JUST an action movie, it would've been fine. If it was JUST a movie about finding your dad/son again, it would've been fine. If it was JUST a movie about finding a new world, it would've been fine. If it was JUST a movie about a political coup/genocide, it would've been fine. If it was JUST a movie about a wonderful new race of people and changing the world, it would've been fine. Etc.
But trying to combine all that? Made it seem overly busy and like they couldn't do justice to all of the issues they were trying to pack in. (and some things about the storyline were built overly-dramatically and therefore got them into a lot of conundra that now they're going to have to get out of-- like what to do with Quorra and how to explain what was so great about the Isos, how to explain what was going to be so world-changing about the Grid, and what to do with Sam and all of the emotional issues they built up for him and which aren't going to magically go away now even though I know they'll write it that way.)
I think it's clunky when one story is split between two or more movies, and nobody'd put up with it if it weren't for an established fandom like Harry Potter
was (I'm not even sure how Twilight
pulled it off [if it did do so successfully]; it didn't have HP
's history and more-than-a-decade of established fans). So I'm not suggesting Disney should've gone that route. But maybe they could've saved some of the issues for another movie, and just touched on the few that were really important.