Ableton has no normalisation function, that is true (except on render)... but I don't see why that's really an issue. Being able to normalise a clip is effectively useless. Normalising a sample is like pressing a 'randomise my levels' button.
Live is designed to generally not edit audio files. That's one of it's features, it's non-destructive. But, Live does edit audio. In fact Live has a brilliant mechanism to edit audio: you can just cut, drag and drop things as you see fit in the arrange view. Then if you want to create a new audio file you can just right click and consolidate without ever having to faff around with audio files and references, and Live never damages the original file.
If you want to apply effects to a sound file you can do that too, but using an effects chain with far more versatility than any linear audio editing package.
You can even tell Live to freeze a channel into an audio stream without you having to worry about the files at all, and unfreeze it if you want to tweak it...then commit it to an audio file whenever you want.
I can't see what more you would want from audio editing that would require installing a third part audio editor... which you can if you want, and Live will talk to it I think.
