Regarding weight, it's not just about whether you could tell the difference of 0.5 ounce. It's that your body will be able to tell afte x hours/minutes of holding - your wrists can sure tell! I want my tablet as light as humanly possible.
Now, many requirements are in opposition - but such is life. I'd like it as light as possible, but at the same time I'd like a long battery life... a tough ask from a physics point of view. Still, that's what I'd like.
So looking forward to the next iPP - if *I* was making a list of "wants":
1)Lighter
2)Longer battery life
3)More connectivity
4)More memory - this is almost unlimited.
And... I think I can get most of these - except maybe "lighter" and "more connectivity".
And really there is no limit to some of these. Like those stories about how "X amount of memory should be enough for anybody" supposedly said by Bill Gates wrt. to some aburdly small amount. It's never enough. Never. Maybe to you it is, I'm happy to get more.
Example - I have a ton of movies and music on external drives - many, many TBs. I want them locally. I don't want to "access" them through a network, or have them in "the cloud". I want to take my iPad with me, and have all my movies even if I'm somewhere where there is no access to external networks. If that's 10TB, or 100TB, I promise you there's someone and not just a few, who would be happy to get it. It may seem absurd today, but anything above 128MB seemed absurd back in the day too. So don't judge what other people need. And you'll find it surprising, that suddenly you find a TON of people want it. That's how you get standard memory expanding in size on phones and tablets. Because people inevitably want more to store photos, films, music, documents whatnot. Even if they stream.
So too here. No amount of battery life is too long. I like to read - and f.ex. the kindle can last on one charge for month(s). I like that. I would not protest and cry if the iPad lasted for 2 days on a charge, or 2 weeks, or 2 months or 2 years.
It's never enough.
You can never have enough memory, enough battery life, and so on. And guess what - technology by and large has been delivering.
So I personally want more of the basics I mentioned above: more storage, more battery life, lighter yet stronger, better screen yet and so on. It never ends. And I'm happy it's so. If you are happy with less, more power to you. I like more. YMMV.