Do you guys have plans to lower the minimum requirements of the game?

That's fairly unlikely. The game will at the minimum require a 

DX11 card

64-bit Windows 7 or higher

Given the advantages of DX11 and the fact that basically no one is using anything lower than Windows 7 anyway. Steam's own hardware stats show less than 2% are running some variant of XP/Vista. And the % of players on non-64-bit OS is less than 7-8% as well.