I was thinking about D&D 5e clerics, and spells.
I think the 5e magic system is internally consistent, and I like the ability to use higher level spell slots for greater effects with spells.
But the whole "your cleric gets one domain" is kinda lame. I guess I'm somewhat colored by having cut my teeth on 3e, where you get two domains, and each extends the spell list, making the cleric of one diety more distinctive than clerics of a different diety.
I also miss the custom spell lists, where different classes can cast a spell at different levels, e.g. flame strike was 4th-level for druids, and 5th-level for clerics. This made different spellcasting classes feel radically different from each other.
In 5e, the only difference, really, between the classes is at what level your character gets the spell slots.
I've read some 2e books, and the whole clerical spheres thing looked super awesome, in terms of custom spell lists by diety. That did really set a cleric of Ehlonna apart from a cleric of Thor, from a cleric of Thoth. Spheres were cool in that way, even if they didn't come with domain powers (3e), or bonus feats (5e).
With 5e, the different domain powers are pretty similar, and most of them offer Heavy Armor Proficiency, even when it seems dubious (really, Life domain equals plate mail?).
I like that the community is doing extensions, and Mark Craddock has craploads of diety-specific feats on his blog, although I've also decided I wish he'd note which domain he thinks that diety should have, just because I think that would help define the flavor of said diety. While I'm probably over-thinkinking that last point, you should check out his blog.