I wouldn't say I've been 'underwhelmed' by the last three albums (since I prefer them as a whole to the first three), but I definitely agree that since we got A Thousand Suns, everything afterwards has felt so tame. The songs are still really, really good (imo), and I've had great fun with OML, but it just seems like the band are focussed on writing great songs rather than pushing what they're capable of. Which is fine, that's their prerogative and they have no obligation to do otherwise, but I feel like often the band conflates a sonic shift with pushing themselves as composers. Maybe some people exaggerate how experimental the album is, but for me that's not really the point. The beauty of ATS to me is that it does retain some pop sensibilities, with catchy choruses, simple instrumental parts, and a healthy dose of repetition from time to time, while also mixing that in with 6 interludes, unusual and sometimes beautiful (Robot Boy) instrumental textures (screaming over piano, rapping over tribal drums, etc.), and (slightly) longer songs with more lengthy, developed sections (particularily the outros of WTCFM, Blackout and The Catalyst). Of course no matter how experimental an album is, you can always find one that's more experimental, but compared to the rest of LP's output, it's the only album that even attempts to lift the 'LP songwriting formula'. Put another way, I think what most of us mean isn't so much 'eschewing conventional songwriting' in general, but more 'eschewing conventional Linkin Park songwriting'.