i'll give u some ideas, take it or leave it.
*Add aroma installer with launcher options, some kernels, some a2sd scripts and apps to choose
*Don't overcharge with ur customs, focus in speed/efficience, battery life, etc.
*Add unique things, to make feel ur rom is the only one, and the best one, not another miui rom, ur in the way to make it, deal with it (for example, adding beats it's a great idea)
Congrats, ur hit in the point to MIUI lovers like me, if u see here, all roms were based in oxy/cm7/sense... no one in miui (well, yes, but discontinued)