Huh...god mode, all/weapons inf. ammo, noclip and level skips. True. These can make the game easier. And, are only really fun for a while. Big Heads, low gravity, extra bloody, these too are cheats, and don't really impact the game in terms of difficulty as much, but are more fun to use.
So, while I won't really miss the former, the loss of the latter is a real shame.
Also, barring multiplayer, the purpose of a game is for one's own -personal- entertainment. Even if the designer has intended it to be challenging and engaging, that means little if you're not having fun. So, it's your's to play in the way -you- see fit. Cheat or don't, only your own enjoyment matters. After all, you paid for it.