My opinion after I saw it (I like the character letter grades as well so I'm gonna narf that)...
-Mutt Williams... B+, actually. I could see the coolness of Mutt, and when he was ONLY with Indy, he was a much more interesting character. Reminded me of a smarmy Sallah, or Sapito, or Short Round... He fit with Indy and LeBouf could act the part well. His sword-fighting was insanely stupid and even more insanely crowbarred into the character. Lame to an extreme. I liked, and expected, Mutt as Indy's son, but I liked it because he did so well as his sidekick. Ironically I could see great new movie possibilities if Ford weren't getting on in years. I don't know that "Mutt Williams and the ________" idea will fly as stand-alone films. Kinda like the TNG crew taking over for Star Trek. Seems doomed to me, and that's from someone who dug the character for the most part.
-Marion... C at best. I see why she hasn't done much in the acting world since Raiders. She's wooden with delivery, and wore "mom jeans" (because I'm not a woman anymore, I'm a mom) styled adventuring pants. It's cool she's there for nostalgia, but her acting was lame and really she served NO purpose other than to intro Mutt as Jones' son.
-"Mac"... D. He truly made no sense whatsoever, and what's with his death? Were we to feel bad? Huh? Was there edited crap that made him even remotely important?
-Irena... C+. I thought Kate Blanchet really acted well for the character, but like Mutt, I found the whole "sword" thing crowbarred into the character for no real reason. Why did she wear a sword? Who swordfights in the 1960's? Indy's whip is a tool, not just a weapon, as established throughout the films, so Irena's sword was just dumb on a whole new level, and it clearly was just so her and Mutt could fight. That's silly and again I say "crowbarred". She was interesting, but really they didn't develope her much or make you care for, or dislike her especially, so she was just meh.
-Ox... B+. He didn't do much, but he was acted well, and played a part in the plot, so I found him a decent character.
-Indiana Jones... A+, without a doubt. Ford is Indiana JOnes and nobody ever will replace that I'm afraid. That means this series dies with Ford's retiring of it. I didn't mind Jones marrying Marion, as I think a lot of people felt that was the best heroine of the first 3 films (I agree), and Ford acted the part well but did the stuntwork just as good. For a guy a bit over 60, that rocks I think.
I liked his relationship with Mutt and feel it was underplayed. They really jived well, and it depresses me that the two characters (and actors) couldn't be put together earlier so more movies with the two of them could be made. I really think there's gold there, that will never be mined. That's a shame. Mutt was the ultimate Short Round sidekick for Ford's Jones I think, and I liked when the condescending attitude of Mutt got turned by Ford as he did his thing and made Mutt look like the kid he was. I thought the acting was at its best when it was really just the two of them.
I was, however, disappointed to see Ford NOT using his whip extensively. This was really a chance to see some fancy work, and I wonder if his age prohibited him doing a lot with the whip? It'd be physical for sure and I could see that being cut due to Ford's body just not being up to it. That's a shame.
I thought the humor involving him was outstanding though, and right in line with the IJ series for the most part. It leaned a little more towards the Last Crusade type humor over the Raiders humor, but I appreciated it and thought it was good.
For the film itself...
I'm with others I believe. I liked some parts, didn't like others. I found some things were "unbelievable". Namely Mutt/Irena's sword fight sticks in my craw, and Mutt swinging on vines was soooooo silly.
I felt all 3 car/vehicle chases were outstanding though, and I really felt that Indy is an ass-kicker still. The story was a little lame though, and a friend I saw it with said he felt it would've been better to just show aliens had been here rather than having an alien alive with the ship taking off... that was pretty dumb and pointless.
I really felt too, that the other adventures were just more tangible... You could relate on some weird level with what Jones was doing and what he was going after. You cared about the villagers who lost their stone in Temple of Doom, and how the Thuggee Cult was corrupt and evil. You could hate the Nazis much more easily than the Russians, and you could also again (in some weird way) "relate" to the artifacts Jones was after against the Nazis... If you were like me, you knew what the Holy Grail was, and you sorta knew what the Ark of the Covenant was... So you just sort of "related" to those items, those adventures, and those films much more.
And to the contrary, the Cyrstal Skull is fairly unknown to most I think, and the whole alien thing sort of took the mysticism of the Ark, the Grail, and the Sankara Stones away. Instead, it's just aliens... Nothing really mystical to it, just aliens suddenly existed and hung out.
Anyway, I generally liked the movie, but it's one that doesn't quite feel like it fits with the other 3 for some reason. I enjoyed it, but I don't think I'll ever enjoy it quite like the other 3, and I certainly won't enjoy it as much as Raiders or Last Crusade, which are my favorites.
And the music wasn't near as good as the other 3 either... Did Williams do it? Because it sure didn't have the "Umph" of the other movies.
Tell me the Desert chase music doesn't pump you up? Tell me when Indy goes to free the children in Temple that you're not pumped by the music to that. And you know the Raiders theme is one of the greatest pieces of music of all time... This film didn't have ANY of that except Indy's theme creeping out now and then.
So, yeah, I'm not terribly disappointed but I wasn't bowled over by this film, and it certainly isn't the best of them. It simply is a fun film to go see, enjoy, and not pick apart too much.
It's better than The Phantom Menace, and I think better than Attack of the Clones too, but I wouldn't say it's better than Revenge of the Sith. If I were to use a Star Wars scale to measure it.