Not so much a fan of their first album, and don't really like their more pop punky kinda stuff, but when they put their foot down and write stuff more in the alternative rock realm (like Careful, Let the Flames Begin and a few others) I really enjoy it and Josh definitely plays a big role in that.
Him and Zac definitely have that brotherly rhythm section connection going on.
In a way, it would be cool to have less pressure on you because your frontwoman gets most of the attention, but on the other hand you'd be feeling like your contributions towards the band and talents are not really getting the recognition they deserve.
If it wasn't for some of those really interesting guitar melodies from Josh and the cool drum parts by Zac, I probably wouldn't have much interest in Paramore as great a vocalist as Hayley is.
Neither are super virtuosos, but always really tasteful and brought something cool to the band that I feel a lot of other bands in the genre don't.
That, and rising to stardom so quickly would definitely take it's toll on your mental being.
For a while Josh and Zac always seemed a bit less into the show than the rest of the guys for a while now.
Josh wasn't even on tour when I saw them live, because of the whole marriage thing going on (Taylor's brother filled in on guitar) and I suspect Josh wasn't that bothered by it, probably even relieved to be off the road for a while.