Will's Take #1: "Now" is a good idea
At its most basic level, "Now" is a typical Paramore song - and that's a very good thing. The band's fanbase will most likely delight in the song's typical Paramore chorus, as long as the listeners don't get weirded out by the odder-than-the-norm opening section and Hayley Williams singing in a harsher style than normal. After all, the distorted power chords are there, the catchy hook of "If there's a future, we want it now" is there, and everything else serves to identify that chorus as a Paramore one. "Now" is standard fare in a fun pop-punk genre, and Paramore has always executed on the formulaic nature of the genre very well. So, when all is said and done, it's easy to see "Now" as a Paramore song that delivers where people expected a Paramore song after all.
What makes it even better, though, is it's a bit odder than most of the band's previous work to date. Whatever forces are compelling Paramore to deviate from their trademark sound - I hesitate to jump to the conclusion of "artistic freedom," but it may very well be true - cause the result to be far more interesting than anyone could have expected. Of course, "Now" isn't revolutionary or anything - it's pop-punk through and through, with a definitive Paramore tilt - but it's still a step, however small, in a different direction. If all is well, fans of the band will be able to look past the initial judgement-clouding "different is worse" and realize that Paramore's fourth LP may be much more varied than any of the band's previous (and solid) releases, which may bode well for the band given that over the course of three albums we thought we came to know everything Paramore was capable of. As "Now" showed, Paramore pulled off an almost paint-by-numbers Math Rock For Dummies far better than anyone could have expected. If they can continue the trend for their full album, all will be well for the band very soon.
Will's Take #2: "Now" is not a good idea
After the hiatus Paramore took between the release of 2009's Brand New Eyes and now, it's unfortunate that their first song (excluding the Singles Club EP) since the break and the leaving of the band's guitarist and drummer will likely only serve to alienate much of the band's old fanbase while not bringing in any new support. "Now" probably won't satisfy old fans because it doesn't have the same pop-punk appeal as their excellent previous two albums had. It's far weirder than the music to which most of the people in the fanbase are probably used to listening, especially in the first few seconds with Hayley's quasi-harsh vocals on "Don't try to take this from me." The heavily distorted and sliding guitar line throughout the song is a serious deviation from the pop-punk norm, and given the somewhat formulaic nature of the more pop-leaning style Paramore has used in the past it's sure to cause many of the band's supporters to automatically call the song "bad" before giving the whole thing a chance.
However, "Now" isn't interesting enough to win over any new fans either. At its core, it's still a pop song, somewhat odd verses notwithstanding. The choruses are just as anthemic as the band's previous work, though to be honest they are weaker than those of songs like "Ignorance" and "That's What You Get." Plus, it's got the standard distortion and typical Williams vocals which previous material featured. Because of this, it's unlikely to convince anyone who hasn't already hopped on the Paramore fanbus to join in, since it's a somewhat weak attempt at experimentation that returns to a typical pop-punk formula for the most part. After all, if a listener of harder, more eclectic rock gave this a chance after hearing about its "mathy" influences, he probably wouldn't be too impressed: to be honest the thing is somewhat boring in comparison to other songs outside the limited sphere of pop-punk. Because of this, it doesn't seem like Paramore will get many new listeners from "Now." Combine this with the alienation of the old fanbase, and you've got a song that most certainly won't help the band much.