you're right from an ergonomic point of view. however, there are a few issues that destroy keyboards as viable input devices for fighting games. at least when you're playing very seriously.
first off, 360s and 720s are close to impossible. forget about playing Zangief. no diagonals also leads to erratic input at times e.g: doing a shoryuken when you really wanted a hadouken. second, most keyboards are plagued with the problem of not being able to handle more than 3 key presses at the same time. EX moves with a charge character? not possible.
you can buy a super expensive "gaming" keyboard to get around the key press issue but you'd rather invest in sticks. i actually like playing on the keyboard but because of these problems, a good pad like the Sega Saturn pad is a way better option. arcade sticks are even better.
