I would say skipping any one album could make people mad about the big change in sound. If you listen to every album in order, you can hear an arguably logical progression, but if you skip even just one album, for example, go Whoracle to Clayman, you can see a huge fucking change. Do that for any of their albums. I think that's actually really interesting and awesome.
Yeah... there were some cries of 'sellout' at Clayman, actually but going from Whoracle to Clayman isn't so bad. You can still hear from the guitar melodies that it's definitely In Flames. You hear it a lot less in Reroute, though much of that is down to production.
STYE on the other hand... take the vocals out and I'm not sure you'd even know it was In Flames, which is kinda sad.