Scratch

Okay, these are just two ideas that would enhance the Scratch experience for me.

1. Menu Multiselect
This would work the same as any other multiselect (hold Shift), but would work for costumes. I have stop motion as a hobby, so this would enable me to easily share my work by choosing the 150-200 frames I generally take in one fell swoop. This could also let people make their own sprites in a paint editor superior to Scratch's and upload them all at once, before they get bored with the idea. And it could help other people GET INTO stop motion, ergo create more animations and improving the average quality of projects (because some sprites are made with two costumes, creating potentially chunky movement that is inferior to other, >5-costume sprites.)

2. ([Colour^] effect) round block
This would sense when the effect is at whatever. Take my Interactive Colour Guy project:
Without this block, he just changes colour and transparency with the mouse.
With this block, he could say "I'm invisible!" when the ghost effect is at 100. This could also be used for colour sensing, making a sprite say "Agh! Low quality!" when pixelated to a certain amount, etc. These are just two things I've tried before realizing they didn't exist. I hope the Scratch Team considers this for 1.4!