I don't have any problem with the writing credits, as long as the five members don't have a problem with the writing credits. That's their thing to hash through.
As for "writing your drum part/bass part", I sort of go along with the idea that it's not really "songwriting". When I was in my band in Philly, there were two main songwriters. And they would get the theme, the skeleton of the structure, and the melodies, but there were a lot of times when the string players (guitars and banjo) would have the opportunity to sketch in our parts; pick voicings, pick rhythms, etc. but in the structure and context of the entire work, it wasn't really "songwriting" as much as it was "performance contribution". There are parts and pieces of things that I came up with and got incorporated, but I don't for a second think I should have any "writing credit".
My big problem is the "James recording in Toronto on his own". I feel like as much as James bitched about Mike being on his ass and telling him how to sing parts, that maybe that's what was needed. I feel like - and I am not including TA here, but if rumors are true, it would apply here as well - that to some degree James is phoning it in. Yeah, there are moments - This Is The Life; The Bigger Picture - but honestly, should a guy of his caliber and his talent and his standing be using autotune in the studio? Put in the effort, sing it live and make it happen. I feel like that is lazy, and I feel like that wouldn't happen if James was in a studio facing John and John and Jordan and Mike while he sang.