Alexander Normal is going to be close to what Coil is with Echo. Alexander Savage is going to be harder than Coil at release, so I'm guessing like Savage Coil. So Normal will definitely still be difficult. It'll still be hardcore content, just a bit easier to get into since it won't have a raid lockout, only a CT-esque loot lockout.
It looks like progression will work something like this:
Casual
- Dungeons
- Floating Continent (CT-equivalent) - patch 3.1 and odd-numbered patches after that
Midcore
- Primals
- Airship content - patch 3.1 and on
Hardcore
- Alexander Normal
- Alexander Savage
On top of this we have Tomestones of Law, Tomestones of Esoterics and Crafted gear. Then we have all the other content that'll fit in somehow at endgame including Hunts and Treasure Maps. We still don't have a solid confirmation of where AF2 will come from (likely tomestones, but who knows).