That's why they're called developer builds, so the developers can implement new things. If a bug or issue pops in, then they can fix it.
If you want to run something more "stable", try the 5.0 release candidates. They're only getting bug fixes to fix regressions that weren't in 4.0.2 (or other critical bugs), so things won't be too broken. However, it is based off of 4.0-6something, so it doesn't have all of the newest features.
For Issue #1, texture packs are more resource intensive at higher resolutions for some games depending on how the pack was made. There was a change some time ago as to how texture packs are handled. So if you had an older version, you may be remembering the old style. What you could try to do to eliminate the issue is enable texture prefetching, which loads all the textures into RAM before running the game.
If I remember correctly, for Issue #2 the blue titles means that Windows has compressed those files to save disk space. It shouldn't have any ill effects for you?
If you want to run something more "stable", try the 5.0 release candidates. They're only getting bug fixes to fix regressions that weren't in 4.0.2 (or other critical bugs), so things won't be too broken. However, it is based off of 4.0-6something, so it doesn't have all of the newest features.
For Issue #1, texture packs are more resource intensive at higher resolutions for some games depending on how the pack was made. There was a change some time ago as to how texture packs are handled. So if you had an older version, you may be remembering the old style. What you could try to do to eliminate the issue is enable texture prefetching, which loads all the textures into RAM before running the game.
If I remember correctly, for Issue #2 the blue titles means that Windows has compressed those files to save disk space. It shouldn't have any ill effects for you?