I don't think so at all. They are a flavor enhancer! I have taken toons from 1 to level 50 with just single origin enhancements and done fine. I/O bonuses let me make a toon with fire, flavor, flair! I can dial in the spirit of my new toon better with them (when I can afford them, I am probably the poorest incarnate in paragon lol ) You don't need Uber bonuses to give a little spice, sometimes a little is all that matters.
To prove my point, I am going to direct you to Spaghetti Bettys gif animation. If she just had the name you think one thing, see the cat girl doing that pully wooly thing and you think "Whoa who is that fun loving hero of paragon!" ........I rest my case! 😀