I say we're not getting either of these artists:
Wishlist (possible artists):
 The Killers
 The Cure
 Sum 41
 Linkin Park
 Green Day
 The Offspring
it's kinda odd that the 3 elton songs we have in RB now are 3 of the fastest tempo songs from his catalog. especially when so many of his most popular songs (tiny dancer, candle in the wind, bennie and the jets, igtwtcitb, your song, rocket man, don't let the sun go down on me) are mid-tempo or slower songs. they keep picking his peppier songs for disc tracks, but it's so poorly representative of his catalog over all.
I didn't say anything about "obvious" or any other act other than Elton. But you could probably apply the same line of thought to any Tier 1 act.
I could go on and on, but the point is that just because we don't have a particular song, no matter how popular, doesn't mean we never will.
Fake Harmonix Facts:
Before deciding to do The Beatles: Rock Band, we were set to do The Lion King: Rock Band. Since then, things have been sour with Sir Elton.
I perform the greatest karaoke rendition of Born To Run that you'll ever hear. And that is no lie.
The Elton John pack was going to include Circle of Life, but when Harmonix didn't get the version that went "NAAAAAAAANTS INGONYAAAAAAAAAAAAAMA BAGITHI BABA" they decided to scrap the whole thing.