Moving it would be udder madness.
A few years ago, the idea of building a station at Vauxhall was down as being a possibility as part of Merseyrail's long term plan. From memory, I think it was down as being third in the list of new station priorities behing Maghull North ( now in service ) and St James ?
I don't know if Vauxhall is still on the wishlist for Merseyrail, but 'd imagine as the waterfront takes off round there, then having a station at Vauxhall would look more commercially attractive than it is now. A station there might be a bit closer than Sandhills, but, even if it wasn't, having two stations within reasonable walking distance of BMD would help split the post match foot traffic.