The pilum is a thing unto itself. I wouldn't call it a javelin, maybe a "heavy javelin" (as wikipedia calls it) if you really want.
The latin for a regular javelin is iaculum and it's smaller than a pilum and purely for throwing. Romans used iacula extensively on their lighter troops...
Like: The general streamlining of play and rules.
Dislike: One spell per day at higher spell levels. If I'm a level 20 wizard, deadlier than quite a lot of dragons (per CR), I want to unload.
Intrigued that nobody is mentioning: Inspiration, which nudges D&D a bit towards them new-fangled...
I remember an ENWorld thread many years ago, I think it was started by a publisher, which was called something like "why don't you buy published adventures?" And by far the most common response was "because I can't fit them into my campaign". Published adventures, at least if you read that...
And in D&D we can have magical authentication of credit. Sendings to validate that IOU, and so on.
Surely this is a perfect business for the church of Waukeen, or whoever has that porfolio.
I am waiting for Mostin to gate in on Eadric + Shomai at an awkward moment, deploy disjunctions and a Gu, and then say "oh, er, sorry, I didn't realise you were, err, umm..."
If you don't mind drinking two fingers of whiskey and squinting, you might just about squeeze GURPS Cliffhangers plus the free lite rules in under that. After all, if you get the free PDF version of the lite rules, it's only one book. ;) [But I must admit that I don't think the Lite rules work...
I bought a book like FRCS specifically to save me the work of making stuff up. Why would I go changing it?
If I wanted to create setting details for myself, I'd use Greyhawk.
Alignment as a thing so concrete it has on/off mechanics (e.g. magic circle against evil).
The WIS ability, rather than the wisdom of the player. To hell with acting idiotic in the name of roleplaying unless I'm a divine caster. Let 'em use CHA.
Armour that makes you hard to hit, instead of...
Those should have been the key points of 3.5e, never mind 4e. I refuse to waste time on PnP D&D while it involves so much paperwork. As somebody said: "twenty minutes of fun, packed into four hours". Oh, add another four hours homework for the GM. [Even Piratecat, possibly the most famous D&D GM...
It seems to me that D&D's meat and drink is "kill things, take their stuff, and level up so you can kill bigger things and take bigger stuff, then repeat".
I don't think they'll ditch levels unless they ditch that.
I'd like it to be setting neutral. But if there's going to be a deity list in the PHB, which I think is a good idea, then "no implied setting" is not an option. But Greyhawk seems to come as close as reasonably possible to not having a setting.