TPM and AotC have many low points, but hey also have some amazing high points, which tends to make people think, "Why couldn't the whole movie have been like this?"
In the case of TPM, some incredibly low low-points drag the movie down substantially.
Low points of TPM:
-Jar-Jar's annoying retardation. I can live with some of it. Understandably, most people can't.
-Child Anakin's horrible acting ("But I-!"😉
-Stupid embarassing jokes, FARTING ANIMALS
-Bad characters, such as slobbering Boss Nass, the two-headed podrace announcer, etc .
High points of TPM:
-Some awesome characters, such as Qui-Gon, Darth Maul, Palps, and Obi-Wan. Qui-Gon fecking owns all with his Jedi Master-ness. Darth Maul is an icon of evil.
-Ian McDiarmid does an incredible job as Palps, as in all the PT movies.
-LIGHTSABER DUELS!!! Duel of the Fates is arguably the best saber duel ever.
-Some awesome landscapes: Naboo, Theed Palace, Tatooine, Coruscant (sp?)
Now, AotC has far many more low points, IMO:
-Wooden acting. For the most part, it's just acceptable, but some of the scenes between Anakin and Pads are simply embarassingly badly akwardly written and acted.
-The feckin droid factory scene. It was added last minute, and it shows.
-More stupider kiddy jokes in the form of stupid droid antics. C-3PO borders on a Jar-Jar level of annoying-ness.
-Some long, drawn out, expositional scenes. Mostly in the beginning and middle.
-The hangar duel is mediocre, definately disappointing.
Here are the high points of AotC noticably fewer than low points:
-The arena scene. All those Jedi fighting, the Battle of Geonosis, the Clones, Mace bein a total badass, the arena beasts, all of it ROCKS!!!!
-Anakin's slaughter of the Tuskens and follow-up confession to Pads. IMHO, these are Hayden's best acted scenes in AotC
^ Thats about it for AotC ^
As you can see, there is an uncomfortable mix of good and bad elements in the first two movies.
I don't think it's fair to outright say the movies sucked, but the good parts are dragged down byt the bad parts.