A program like Defiler (search in Modifications forum on Titan Quest Forums
) is both good and bad.
I used the program to test a few builds at level 65 to see if the end result was what I was hoping my character would develop into. Using the program to tweak until you find something you're happy with has its uses. I would rather earn my levels, but would understand if a player choose to create a level 40 something to join friends who had already been playing the game for months together on say LAN.
On the other hand, giving yourself every skill maxed from every mastery along with a million hit points and energy and stats in the tens of thousands makes the game less enjoyable. Sure, its fun to run around in "god mode" for a little bit and breeze through things, but the long-term playability of the game goes fairly fast as cheats are increased. I know a person who will only play games with extensive cheats; if there are no cheat codes he will not play.
In the end, to each their own.