I just bought mine and I will be hanging onto it for as long as I possibly can, since I can't afford to replace things like this very often. I can see a market for the features you describe, though I'm in the section of the market which appreciated the Nexus 7 because it offers a great spec for a relatively low cost.
5. Better speakers. Both the Nexus and iPad speakers are lame.
*winces* Please don't use "lame" as an insult - it's really disrespectful of people with disabilities.
I'd have been happy to pay an extra tenner or so for better speakers, since I will be using it for listening to audiobooks a lot. Speakers do seem to be overlooked on computers a great deal, and I always notice this whenever I'm buying a laptop. I'll ring a shop or manufacturer to ask which laptops have good speakers, since as well as the audiobooks I watch films on my laptop instead of having a TV, and will be told either, "Oh, they're all fine," or, "All computers have rubbish speakers, you must get external speakers if you want to hear any sound at all." Which is total nonsense, as computer speakers vary considerably, and like most people, I just want to be able to watch a film from six feet or so away and hear it clearly, rather than needing DJ-quality sound. Considering how popular online videos are these days, it's high time that manufacturers caught up with the fact that yes, people *do* care about the quality of the sound.
7. Better battery. Maybe even removable.
A longer battery life never hurts, but I manage fairly well. I don't think I'd have paid extra for it, unless it was a fairly low price increase and a mammoth difference in how long the battery lasts for.
I think one area which needs more development is accessories. At the moment, it's very patchy indeed, and new tablet owners find themselves having to buy all sorts of bits and bobs to get things to function. Tablet manufacturers are starting to produce accessories, it seems, but they're not that common and the prices are very high. They need to accept that right now there are a lot of cheap accessories they'll be competing with. ?25 for an official docking station might have been worth it if it had come with good-quality speakers and an extra charger, for instance, but it's basically a stand which replicates the two ports it's covering up, and I don't think that's worth that amount of money.