I'm not too fond of it, but at least P isn't too common.  One major drawback of Dvorak is that it assigns "L" to this key, which is needed far more often.

I haven't tried to learn Colemak yet, but given that it retains one of the major problems of the QWERTY keyboard, I'm not sure if I want to.  I'd rather keep QWERTY but with the A and J keys swapped over.

I note that something like this was tried with the proprietary XPeRT keyboard, but it doesn't seem to be well thought of round here.

Thanks for that.  Apart from XPeRT, it seems to be the only one on this list that doesn't place the A in the same unsatisfactory position.  Seems to be some sort of blind spot amongst keyboard redesigners.

Why not?  It really is the principal thing that annoys me about QWERTY.  I probably wouldn't have even considered switching otherwise.

I don't find either T or N to cause a great deal of difficulty, as they're both struck with the index finger.  I agree that J, and to a lesser extent K, are a waste of space on the home row - that's why I proposed swapping A with J.  I suppose it might make sense to swap K with another key as well.  (I note that the XPeRT keyboard has a second E key in this position, which struck me as an interesting idea.)

Having the commonest letters under the strongest fingers strikes me as the most sensible principle for keyboard design.

My thoughts exactly. In my opinion, A is in a good place where it is, because (on an ANSI keyboard) qa/aq bigrams are none existent, therefore the left pinky only has to take care of of this one button, unless you're using an extend layer and it's mapped to Caps Lock (like me, although personally I have no problem with using the left pinky to type A and use the extend layer).

Swapping J and A would indeed increase the same finger bigram frequency. I've just run a quick test on stevep99's layout analyzer for comparison:

If you want to make only one change, bringing E to the home row (swap with K, same position as Colemak E) will be much more beneficial than moving A within the home row.

See for example this topic: What single change would improve QWERTY the most?  Quoting from it:

All right, so how about a three-way swap?

E to the K position
A to the E position
K to the A position

The "QWARTY" keyboard :-)

That would improve the accessibility of both E and A, without causing any major bigram problems that I can see.  AD and DA are both fairly common, but no more common than ED and DE (I'm guessing).

I ran "QWARTY" through the layout analyser and got this.  The top same-finger bigram was AD on 0.005161:

                position    bigrams   total
finger 0    0.01551    0.00066    0.01617
finger 1    0.13029    0.00578    0.13607
finger 2    0.20279    0.01853    0.22132
finger 3    0.61795    0.05373    0.67168
finger 6    0.53420    0.04154    0.57575
finger 7    0.30046    0.02206    0.32252
finger 8    0.26045    0.02517    0.28562
finger 9    0.05943    0.00454    0.06397

total *    2.12108    0.17201    2.29309

An improvement over QWERTY in both respects.

Hours of endless fun!  I think I've just discovered a new toy :)

According to the layout analyser, this layout is actually worse than the one only swapping E/K.

(But still better than Qwerty, due to moving E.  So it seems you have put three steps forward, then two steps back. ;-))

The map seems to imply an overestimate on some of those smaller languages mind - I guess they are just colouring in regions based on the language name rather than suggesting the languages are widely spoken in the region coloured. Most people in Ireland can't speak Irish and even fewer people in Wales can speak Welsh.

I think the QWERTY E position is an easy one to reach, because the middle finger is longer than the other fingers, so you can keep all your other fingers on the home row and still hit it with ease.   The QWERTY "E" and "I" keys are probably the two most accessible keys on the top row.

In practice, I almost never hit the "A" key with my little finger as I'm supposed to.  My hand moves to the left and I hit it with my ring finger.  (I hadn't even consciously realised this until I thought about it just now.)  That's probably why I make so many mistakes while typing - my hands are constantly moving out of position to accommodate the awkward keyboard layout.  I suspect many QWERTY typists do the same sort of thing.

When I tried to learn Dvorak, I made a point of always keeping strictly to the correct finger positions, and one thing I noticed that there was a lot more strain on my left-hand little finger.  The "A" key hadn't moved, but my hand had moved.

So I think I would rate QWERTY "E" position above QWERTY "A" position, myself.

I'll have a play around with the ratings then.  Thanks very much for coming up with the analyser - it's extremely useful!