Hi,
you does not need to remove it, you should add following CSS code in your template to set height

#member-registration .controls > input, #member-registration .controls > textarea, #member-registration .controls > .input-prepend, #member-registration .controls > .input-prepend input {height: 33px !important}

33px is the height from your template.

Normally BS2 and BS3 template use padding to set height of input, instead your template use a height. Our code is necessary to fix problems with prepend/append buttons, so we recommend to use something like:

#member-registration .controls > input, #member-registration .controls > textarea, #member-registration .controls > .input-prepend, #member-registration .controls > .input-prepend input {padding: 6px;}

with 6px of padding you should have same result as 33px of height