Sorry but i expect better battery life than a 5 year old touch 4. Don't think that is an unreal expectation. 4.5 hours with everything turned off is not good. Going from 80% to 20% in less than 2 hours is terrible, watching video or not.
Is it realistic when you consider how thin it is and the the size of the battery. You can have all the expectations you want, but you can't overcome battery technology. Until Apple comes off this thin craze, which I don't suspect they will this is the nature of the beast. If you can't live with it, then speak with your money, don't buy it! It won't change anything, but that is your only option. Hopefully you can find something else to buy that meets your needs.
I have found the battery meeter isn't very accurate. I've had this thing stay on 20% over an hour before dropping. Again, if isn't working for you speak with your money!