I haven't been that impressed with many halftime shows at all. Maybe it's one of those "gotta be there" things. I was pumped for The Who and they sucked. I've seen them in other live performances and they rocked. I kind of like when "special guests" come in and sing with together. Sometimes it works pretty well.
But I just don't get Elvis. He could sing, granted, but he didn't seem to stand out in ability IMO. Not a WOW! singer. He didn't write songs. I don't know. I mean, you can take Bob Dylan for example. His singing SUCKS, but you can't deny he had an incredible songwriting ability. Even the Beatles (who I'm not convinced were overrated, but aren't one of my most favorite bands) wrote their songs and many others and performed on their own instruments and took Rock and Roll to a whole nother level.
Maybe it comes down to I just don't appreciate Elvis's voice? It does nothing for me. Maybe I had to be there to experience it? (I remember watching him on a tv special with the white jumpsuit and sparklies when I was young) I can agree that he opened the door for a lot of other musicians, but I also believe that if it wasn't him, it would have been someone else. I think the time was just right for him. Maybe I just can't appreciate him from the future when music has evolved the way it has.
If you compare Elvis to another Hugely Popular performer, say, Michael Jackson, I'd still say MJ comes out on top. They were both huge and influenced a future generation of performers. MJ wrote a lot of his music, danced and performed like no other, and could sing like crazy. Even Madonna was a lot like Elvis in the way that she influenced future female performers. And her voice wasn't even all that great too...
It's very hard to compare someone in today's music with Elvis, because they will have the advantage of having the modern effects and autotune garbage is so popular today. (I like it for a special effect, not as a crutch). You can't tell who's real and who isn't. I'd really rather hear a live, pure voice, with all of it's flaws, than a pitch perfect autotuned performance.