There are also some small things: coffee makers, pool towels (though I'm told all values now have these), I think one of the values might still be missing in-room hairdryers (though most have these now), make-up mirrors (only at some deluxes), more resort activities, dorm fridges (they aren't very cold, but in the value resorts you have to pay $10 per night to get one), fresh flowers in lobby.
I've also personally noticed a different level of service. It's hard to describe, as most of the resort CM's do a great job. At the values though you are slightly more on your own. At the deluxes, CM's spend more time going over details with you at check-in. I think this has to do with higher staff ratios. But not all service at all resorts on all visits will be equal or up to snuff. you could get an excellent or less-than exceptional CM at any resort.
That said, many folks enjoy staying all the resort levels, as has been pointed out many times. Still, I think - just as folks act differently when they are dressed in their Sunday best- conduct expectations are slightly different at each resort. That doesn't mean conduct is better or worse, just slightly different. Indeed, often the folks who are most willing to talk to strangers and offer help are at the values.
We also noticed for us, that - even if you WANT to spend time at the value resorts - you have to leave to use the dining plan TS credits- no matter the weather. Some of the your trekking will be out in the open.
At Deluxes - depending the TS places at your resort might be too popular to get a last minute table, should inclement weather cause you to rethink a dining reservation. At the mods, the TS places aren't in as high request, but they are available.
All resorts have unique theming. There is more detail to the mods and deluxes. Only the All-Stars really have Disney characters for theming. You'll only see things like fresh cut flowers at the deluxes. All resorts are very clean, but room keeping tends slightly better at deluxes.