Your sight radius would be improved if you left the front sight block alone, and mounted a sight on the dust cover.
As you describe it, you're really not gaining anything.
I was thinking of just sliding the FSB back to the front of the gas block, so I would gain about 2-1/2" to 3 inches depending on where I mount the rear sight. Probably not worth the trouble, but it would help me with my getting a better sight picture with the rear sight moved back, but then new bifocals may help too. Plus I do like the look better, just my opinion.