If you are taking into account Randy's feuds since losing his title to Henry, then I would say that yes, he is being used at a level below which he would normally wrestle. Make no mistake, Orton is the biggest name on Smackdown and by virtue of his position he should ideally always be either holding or chasing the World Heavyweight title. But I think that him stepping aside from the title scene has helped other performers develop, most noticeably Sheamus. Sheamus has a similar gimmick to that of Orton, the badass babyface, except that Sheamus is more jovial, and he would not have been able to rise to prominence as a face with Orton dominating the title scene.
Also he has given a rub to quite a few performers in the time he has spent away from the title scene. Both Cody Rhodes and Wade Barrett have benefitted from their feuds with Orton despite not winning much. They both look better now as compared to what they were before feuding with Randy. The feud with Kane may not seem like a big deal in front of some of the big matches that have been announced for WrestleMania but I have little doubt that it will be a pretty good feud which may even end in a very good gimmick match at Extreme Rules.
Overall, I do not think Randy is upset with the position that he is in. His finisher still attracts the biggest pop out of any move in the WWE and recently his promos have been very well recieved as well. The "My name is Randy Orton" is a simple but hugely effective line. Orton is at the peak of his career and his popularity does not seem to be waning even a little bit from working at this level just below the main event scene. It could even be that he has suggested this move for the betterment of the company as it has allowed WWE to create new stars like Sheamus, Henry and Daniel Bryan.