Seasons 3 and 4 are worse then 1 and 2 of Robotboy. Don’t get me wrong, they have good episodes like Up a Tree and Robolympics and better animation. But at the same time, the editing is worse, the action scenes are considerably worse (though there are exceptions like Robotboy's Fifteen Minutes), an increase in gross-out humour (Bob Camp directed those seasons, he was a co creator of Ren and Stimpy so this may come as no surprise), among others.
But then again, these seasons introduced characters like Affenkugel, Ludwig, Hexx and Gilbert, and brought back Protoboy and Robotgirl.