[objclxt]

One important thing that's new in Scratch 2.0 under the hood is the transition from the .SB file format (a rather complex SmallTalk object store) to a ZIP based bundle containing all required media along with JSON encoded scripts. The upshot of this is that consuming Scratch files in other apps should be a lot easier.

That said, one downside of Scratch 2.0 (at least in my view) is the migration to a Flash based editor/playback engine. And I don't entirely blame MIT for this, because Scratch 2.0 has been under development for quite a long time. Five years ago, Flash maybe seemed more appropriate than it is now.

[andystalick]

Actually, there is at least one web-standards-based playback engine - http://wiki.scratch.mit.edu/wiki/Sb2.js

Although the content-creation tool sadly remains in Flash.

[TazeTSchnitzel]

Flash sucks, but I'll take it over the old Java applet any day.

[vanderZwan]

I dunno, the latter is much more stable in my experience.

[pie]

I've talked with the Scratch team and I believe they went with Flash to serve the many schools with low-end machines and older browsers.