don't think it's much of a simplification, think it's right otm. now there are merits & negatives to axl's approach (many, many more negatives) & that's where you could write a book from, but in terms of 'artistic differences' what you've said is exactly what went wrong with the band.

niven nvr woulda had the power to have stopped OIAM appearing - in Great White he had input even into the songwriting but he had nothing nearly as close to GnR or Axl especially in terms of relationship. if izzy nor slash couldn't stop the song appearing niven assuming he could/'ve seems outlandish.
OIAM is a brilliant song poss top 5 GnR.

Don't Cry, Brownstone
who wrote Rocket Queen?

while i agree with the opinion Slash & Axl are enough to make great GnR music, Izzy kept them grounded in accessible immediate r n' b-based rock n roll. neither slash nor axl are able to write those 'simple' solid rock n roll grooves as consistently as izzy, axl & slash's strengths lie more in creating epic stadium-sized songs - SCOM is the most typical recognizable/poppy kinda thing slash wrote on AFD & even that was mostly unintentional.
but for most of the people who say that GnR died with izzy it's a cop-out & the kind of thing people say to be cool, 'cause izzy was obv the coolest in the band ('cause he was the quietest & didn't give people much to dislike him for). they forged a singular identity & while that was down to the shared vision of the main guys, axl & slash's attributed were/are definitely the defining features of GnR & give them their individuality - if izzy had been in charge & axl not a control freak with grand ideas GnR woulda ended up like the new york dolls (not that that's a bad thing, but y'know GnR are more like the stones n zeppelin due to axl/slash that's what i'm sayin')

izzy didn't play on locomotive did he? the writing musta been on the wall for him for some time that his place in the band wasn't significant - his guitar parts on the UYI are definitely nowhere near the levels & interaction as on AFD. & he musta never cared to try to wrestle back some creative - or otherwise - control. a shame 'cause i do think his presence & vibe are missed. that's not to say i don't believe something like Shackler's Revenge wouldn't have made a GnR album if izzy was still in the band - even when izzy was there axl had already begun to do whatever axl wanted, on album & elsewhere - but there'd definitely be a lot more blues & groovier rock n roll.

ftr - TAY is maybe my fave AFD tune. i've noticed it gets a bit poo-poo'd on here but 4 me it's everything great about that record inside 4mins..

good set
better nice n early.

i thought they were axl's idea but that slash was responsible for hiring & arranging them.. think i need 2 re-read my GnR history books..