-W/o loads vs With loads double time system. -Support for milliseconds

Less important: -Tickboxes for SS / RTA / RTA-no-QS and script/no scrips, so we can keep it 1 category and not 6 since some people like to bitch about it.

Since there's Old Engine and New Engine, wouldn't it make sense to have them as separate games and they can define their own categories (any%, etc)?

That's how it would be done for games that are released on various consoles (eg Donkey Kong Country, Perfect Dark).