The feed ramp on my 1911 is all scratched up and I was wondering if this is something you could polish to make it more reliable with hollow points and wad cutters?

Yes    get some 1200 grit paper  

so I have to use a dremel and I just polish it up ?

If it's a used gun sounds like someone might have used a dremil on it.   You need really fine sand cloth or paper on it till you don't see those scraches  on it.    Smooth is what you want.  The problem with large mouth or hollow points feeding is those rough edges catching the jacket and causeing those stove-pipes.

You don't want to get into the metal of the ramp.just polish it smooth with what ever(some dudes even use jewelers roughe)  

 Bob  

If your 1911 is anything like a few I've had, there will be some pretty deep machining marks still on the feed ramp.

You can make them smooth with 1200 grit or jeweler's rouge, but they will still be there.

You can remove them entirely with some 240 grit sandpaper wrapped around a dowel, then polish with finer grits and finally jeweler's rouge or some other fine buffing abrasive.

Be sure to follow the angle of the feed ramp precisely, don't round off the corners or change the angle.  Take your time and do a careful job.   Don't remove any more metal than is absolutely necessary.

Most pistols will function fine after simply smoothing the surface out, they don't require an absolutely flat surface.