@rinigus, yes, you are right about the sizes - they are already changed here. 4 GB is definitely better than 2,5 GB which was way too little. I had to remove quite a lot in root partition for every update the last years. For some of the version 3 releases it required almost 700 MB free in root partition, so even if downloaded in home it could get hard to fit with OTA (does the method differ between device types?). I would argue 4 GB is the minimum.