It could get ugly with a bunch of empty rows and your code to find them and update them and all that could get ugly and hard for someone else to come into and make changes. Heck in a year if you don't touch the code again it could make it hard for you to come in and make changes.

If you are worried about size and memory not being properly re-allocated after doing a delete you can always perform some kind of "packing" function on it.

Almost all DBs have sometime of function for packing the data.