Many, many of the Sedwick descendants have changed the spelling to Sedgwick. I would even guess that today more descendents of Thomas Sedwick spell the name Sedgwick than do Sedwick.
I'll also guess that if we ever find Thomas Sedwick's ancestors, we'll find that his name was Sedgwick, and that Sedwick itself is a variant, a clerical error in early Maryland. It is possible that Thomas came as an indentured servant, and that he had no clue how to spell Sedgwick. Have you ever seen any evidence of Sedwick in England?
All this having been said, I guess the real question is this:
Is the Sedgwick/Sedwick/Sedgewick community better served by fragmenting into several groups, so each can concentrate better on its own, or by working together, so information can be better shared? The basis concept of Sedgwick.org is that the latter is better.