What are the BRP Essentials?

The Tinkerage has great respect for Chaosium's Basic Roleplaying, or BRP, a system that feels rules light even though it's packaged in a rules-and-options heavy compendium known as the BGB, or "Big Golden Book".

Now Chaosium has announced that BRP will become BRP Essentials, the core 32-page rulebook for a BRP family of games. But what are the essentials of a BRP system? Are they BRP itself, Runequest, in its current or past incarnations, or even one of the OGL offshoots, such as Mongoose Runequest (MRQ), Legend, or OpenQuest?

Here's a purely speculative take:

Characteristics: STR, CON, SIZ, DEX, INT, POW, CHA (or APP)... EDU perhaps? They go back a long time, the roughly 1–20 scale connects us to the early RPGs. SIZ modifies HP, but do we ever roll against it? Could they sit directly on a percentile scale and still work? I like characteristics to modify skill scores. I like a characteristic roll when no skill applies.

Skills: Percentile skills are the core of BRP. Move them around, rename them. The only thing that puzzles me is why Resilience is a skill in certain versions: you can train to get tougher and fitter, that's how CON and STR go up, but how can you learn to be tougher, especially as you age?
Adding up skills and skill category modifiers is the longest part of character creation, so can this be easier? The MRQ system of base skills defined by adding characteristics is tempting, and cuts out skill category modifiers.

Rolls and resolution: BRP uses a 5% critical and a 20% special. Other version derived from MRQ use a 10% critical. This is a big difference. Which is more essential? Well, players love to roll specials, and specials that happen about 20% of the time when they succeed feel about right. But 10% is easy to calculate.

Combat, Initiative, Hit Locations: Action points, Strike ranks, DEX ranks, combat actions. Options make combat more tactical, but draw out the encounter. Over time, I'm found that most excitement in combat comes from setting, strategy, and fast resolution. I favor the simple system of DEX-based initiative. And no hit locations. They slow down the action, impose odd results, and make designing and running encounters a chore for the GM.
Are there good reasons for different critical types by weapon (slash, bash, impale)? Surely, but in practice we usually just roll double the damage dice and move on.

Experience: The elegant system of rolling against a skill once it has been used for steady, incremental gains through experience is surely one of the essentials of BRP.