I think that would add a level of complexity to the game they are trying to avoid.
No, [MENTION=80924]fjw70[/MENTION] 's suggestion will
decrease complexity of 1st level characters.
If a group wants to run a lower power campaign I think that is achieved easily enough. DM's can always limit options at first level. For example, as a DM you could start the game and say nobody gets a specialty until level 3. With just their class and possibly background that would bring the power level down.
Not enough. Some groups can choose to never use backgrounds and specialties, and that is all they can do safely (i.e. be sure that all PCs are toned down the same). But that includes just skill bonuses, a trait which is used outside encounters, and just one feat. Taking them away is not really going to lower the power level significantly.
You cannot lower the power level in other ways easily, because everything else is asymmetric across different classes and races.
For example, you cannot decrease the number of spells known or per day of 1st level wizard because there is no equivalent for the fighter or rogue class, and you'll be on your own figuring out what you should then take away from other classes to end up with a balanced lowering of everyone. It can be done but is not at all easy enough.
Viceversa, starting the game at a higher level everyone is always a piece of cake.
1st level sets the minimum power level for everyone without having to worry about maintaining balance yourself (not that I would worry very much about maintaining balance, but I'm speaking for others too) because presumably it has been measured by the designers. Lower than that, the game leaves you on your own, so it's a legitimate concern for those who like to start a campaign with frail PCs if they think 1st level is already too powerful.