I am going to sound like a MS apologist, but that is not my intention. In fact, I think quite a few things were executed poorly in their Surface line (most of that revolves around the mere existance of RT). Anyway, I will try and repsond as best I can here...
Let's look at the first use, tablet use.
As a tablet, the Surface pro is heavy. And thick. Call me limp wristed but it weighs significantly more than an iPad 3/4 which after prolonged use can get tiresome if using it one handed. All your tablet based tasks (web browsing, checking email, casual games etc) are far less demanding than an i5 CPU calls for. So you have all that power just wasting battery life. (More on that in a minute)
So as a tablet, it won't be a very good experience. Certainly more comfortable, cheaper solutions are out there. (See iPad, some Android tablets)
I think there is very much merit to what you are saying. At the same time I can say, from my relatively frequent travels, that I see almost nobody using their tablet one handed for any length of time. I generally see people resting their tablet on their laps, the tablet, the armrest, etc. When they are holding the thing upright, it is with two hands and they are, again, resting their elbows on something. Where I do see this device being completely inferior is reading a book, where you very much are holding the device to your face for hours at a time.
That brings us to the real drawcard of Surface Pro. It runs a full x86 OS and packs an i5 so you can run all your legacy apps! Great huh? Well for a start, they will be complete garbage if you try run them in tablet form. The windows 8 UI is designed for a touch screen, but all your legacy apps most certainly are not. Good luck using menu's and buttons on a 10" 1080p screen. I hope you have small, accurate fingers. (Sure you could use a stylus I guess but.....eugh)
Legacy devices aren't going to be used with the touch interface. They are going to be used in conjunction with the keyboard and trackpad combo, or a mouse. At least, that is the assumption I have made. I definitely don't expect MS to think that we are going to use legacy applications on the touch screen.
So you would set your Surface on a table, deploy the kickstand, attach your Type cover keyboard, and then what? Well then you have a laptop with a tiny screen, a cramped keyboard and trackpad and a screen you cannot adjust the angle on. Oh and I hope you have a nice flat tablet at a specific height available because you sure as hell can't use it as a LAP top, not with that bendy keyboard cover and kickstand. And for any serious work you would probably want to attach a mouse. At which point, there goes your 1 USB port. You could attach a USB hub I suppose? (Or just get a laptop with more than 1 USB port)
I don't buy the laptop with the tiny screen being an issue. Why? because netbooks were a popular buy up until recently. The MacBook Air is still a popular buy, and at 11", while it is larger than 10.1", it isn't an earth shattering size difference.
As to your mouse input, I wouldn't dream of plugging anything corded into something like this. Luckily we have bluetooth mice, and have had them for the better part of the decade, that would be quite suitable for something like this.
This brings me back to the battery life. The Surface Pro is totally useless for school use. The battery life is claimed by Microsoft to be HALF that of the Surface RT. So let's say 4 hours. At best. That one fact alone makes it instantly useless for schools, who are currently all rushing to implement some sort of iPad/tablet use for kids.
This is the achilles heel of this device, and something no amount of apologies will make up for. While I am still eager to see real world stats, I am not terribly hopeful. I think MS should have waited for the next gen super power efficient chips that would likely double battery life, even if it would be at the cost of raised production costs. I think expecting a real computer to last all day is a bit unreasonable, but expecting it to last more than four hours is not.
So as a Tablet, the Pro is too bulky and pointless for legacy Windows apps as the UI would be unworkable.
As a Laptop it's a poor, comprised design with poor battery life.
I think you summed things up way too simplistically here. Battery life is certainly a problem. Everything else, well, really isn't.