Hard-to-reach buttons could be for convenience stuff like map, inventory, etc.
I prefer to rest my thumb on 5, so I can roll up and hit 2. 8 is just a bit further back, the keys on either side of those three keys are easy to hit with just a tiny roll of the finger. 10, 11 and 12 I usually assign to less than critical skills/functions because while my thumb "knows" where they are, they can be a bit uncomfortable to use often.
all you need, the rest is on the keyboard anyway.
the program has guild wars pre-programmed and is multitask build, the naga has a ton of buttons that just grimps the thumb, most of them are simply useless.
i rather have a hand that doesn't hurt while playing a game rather then a mouse that just makes a ton of stress on just one finger, making the game a hell to play.
I have been using the naga for a while and I was afraid of just what you are saying but honestly, once you get used to it, it is not a strain on the thumb at all, in fact I hardly notice it in every day use. The one you linked seems a nice alternative though, I like the idea of keeping it simple. The advantage of the naga is that it has functions directly available without having to resort to a modifier key (which is handy if modifiers are not supported) while the Kone seems to have a very functional design with minimal bulkiness.
So, overall this mouse is recommended, right? Does it work with all games? I have been kicking around the idea of picking one up for GW2 & D3.
I had a razer back when, and even then it worked with all games. It came with software that let you program buttons to take over keyboard functionality. I assume the same is true with the new mice.
Note that specifically for action-RPG titles they advertise the Naga Hex.
Either way, it takes some practice, but it's well worth it.