Really? When you holding device in one hand I agree with you.
But if in Landscape mode I guess you hold it in 2 hands and the way how I am holding it will determine the angle and arc. Are your fingers really sticking out from the coroners of device like 45 degrees?

There is another one problem in MicroB you need to use interactive mode so... in this case I had to leave those areas empty.

And there is another one issue:
When you would like to make an symmetrical solution is just impossible regarding to the layout of normal keyboard.

Those parts you can make symmetrical.

left hand__________right hand

q_w_e_r_t_y_____ u_i_o_p_[_]_
_a_s_d_f_g_______ j_k_l_;_'__
__z_x_c_v_________ m_,_._/__

but

___________ h
___________b_n
remains