meekstone will
hinder you more, than anything, as your big creatures won´t untap.
winter orb is a good addition as you dont care about having much at all.
shocklands are avaiable in every colour pair and like the og dual lands, have to basic land types, there are 3 you can play, as you have 3 colour pairs.
isochron scepter can help but not with
dark ritual, as you have no consistent way untapping. speaking of untapping- the
staff of domination won´t do much either- as i dont see how you are going to use it effectivly.
cards i would not play are the following:
mardu banner (too slow)
exquisite blood (lifegain is cool, but useless as you just want to kill your enemys, with
sanguine bond and shit in a lifeain deck its good, but not in that type of aggro deck you are building)
honorable passage (unneccessary)
cave sense (not that great)
jandor´s saddlebag (there ae cheaper alternatives if you want
vigilance)
quicksilver amulet (that is what you use your commander for, also 8 mana to something on the battlefield...)
cards you might also enjoy are extra combat cards like
seize the day, i run it in my
feather, the redeemed deck and almost everytime kills somebody out of nowhere, but in the end, its pesonal preference ^^