As they essentially drain all of your cash flow at a time when you need it most.Good Luck and make sure you do some research on raising money from friends and family as they are most likely your best resource for loans, with reasonable non/loan sharkish sets of terms.

Aggressively putting a well done french drains around the uphill side of the house will do a lot for your water issues.  

To give some background; I bought my rental property in Nov 2012 and on the day of closing did my final walk through of the house, while checking out the crawl space I noticed a small amount of water around a drain in the floor.

You also need a mirror or medicine cabinet, faucet, drain, p-trap, supply lines, new shutoff valves and who knows what other fittings.

Fixtures drain slowly.

Or would this be in effect pouring money down the drain regardless of how much enjoyment that added natural light brings?

I've decided to buy a more robust digital dehumidifier and have a plumber drill a hole and drain it to the outside so that tenant does not have to manually empty the reservoir every few days.I'll let you know if anything changes.

Convert from screw in fuses to breakers, run new plumbing lines, auger clogged drains and other big jobs....that's what I hire out.

Also, the floor had some big cracks and looked bad and this was a home built in 1904 with a brick basement, common for the area which is a hot area of higher priced older homes here, so I had the three walls removed and replaced with new block walls, a drain tile and sump pump system put in and a new floor poured on top.

If you dig a 2' deep by 2' wide trench around the high side and down the sides of the home draining away from the home, place perforated drainage pipe on top of 6" of 3/4" gravel and tie the downspouts into that, then fill the trench up with the gravel you should never have another problem with the water in the house again.Also excavate the lot on the high side down at least 4" below the slab top.