Class based and level based:
Depends. In the case of 4e, I think that it works, though I'm not sure if I would have stretched it across 30 levels. There may have been alternative ways to achieve similar results but without as much need to design for 30 levels of player-facing content.
Check. I just wish that they got the math right the first time around and could actually design adventures around that visible design that they made for themselves.
Classes with clear purposes:
This is a big one for me. 4e not only delivered in clear class roles but also in providing clear class themes (for the most part*).
* I'm still scratching my head about "the Seeker." It was a ranged primal striker, which was fine, but the name and archetype fantasy seemed murky when compared to its primal peers: i.e., Barbarian, Druid, Shaman, and Warden.
Agreed, but see my earlier point about doing this across 30 levels. D&D 4e arguably could have created four tiers of play across 20 levels instead of three tiers of play across 30 levels.
There were some questionable balance decisions, and I think part of the issue stemmed from having to design material for every level. It may have been easier to Balance with less moving parts.
Check.
Defenders that really defend:
Support that matter:
Tactical Combat:
Check on all three.
Amen. Rolls against defenses are far more intuitive, IMHO, than saving throws.
Agreed.
Intuitive encounter building:
Check.
Check. Compared to many other settings before it, the Nentir Vale was easier to wade through as a player and GM because there was less lore clutter. Its barebones nature made it easy to customize for GMs and to plug-n-play characters for players, because its setting themes were more important than the nitty-gritty lore.
Cosmology for Adventurers:
Check. Moreover, the cosmology is built around broad themes that were easy to understand. This also meant it was fairly easy to understand the cosmic role of a new monster in a way that amounts to more than its alignment.
Check, though for me, I think the bigger point is how 4e set clear expectations surrounding the three tiers of play (i.e., Heroic, Paragon, and Epic) and the sort of threats that tonally the PCs should be facing.
Separation of combat magic and utility magic :
Magic doesn't always do it better but is convenient:
Check.