I don't know how old the OP's gun is, but current production Colts have pretty usable sights and they are available here and there.
Older stuff, I have a set of the (defunct) King's Hardball and a couple of the Novak Concealed Carry sights that fit the GI dovetail.
I don't see the sense of a hundred bucks worth of milling machine time for a fixed sight, but it is getting hard to avoid.
You still have to do something to get the right height front sight. A well done stake-on will work, but unlike the rear, I would pay to have a cross dovetail cut for a really stout installation.
Yes, it will "hurt the value of the gun." Assuming that it is in pristine condition and the older the better, any modification will reduce its resale value. But why care? Are you going shooting or trading Cabbage Patch Dolls?
There are the Novak Competition sight
Harrison Retro and 10-8 sights look like larger than life GI sights.
MGW is good, too.