Joining surfaces and eradicating the edge

sometimes i find myself cutting holes in surfaces and then closing them up again when i change my mind about them. this really disrupts the continuity of the form visually and in terms of the workflow. Is there any way to truly merge surfaces together rather than just join them?

Those are two different things you ask:
if you cut a hole in a surface, you can use the Untrim command to remove the hole;
merging surfaces without joining is possible if both are untrimmed, using the MergeSrf command.

Thanks for the reply. is there anyway to do it with trimmed surfaces?

The merging of surfaces? No.
Unless you reconstruct the surface so that a natural edge is at the trim - but that will only be feasible in a smaller subset of cases.