To be honest I am not seeing the big deal. You can get a extra spell known a level behind the highest you can cast which is a level behind the wizard. An extra 2nd level spell at 6th level isn't something as a GM I even worry about to be honest. A wizard base spells known without counting any thing else at 6th level are 20/5/4/4
the human sorc could have 8/6/3/1
Just not seeing an issue here
There is no issue. Not really. Fear of "power creep" will be the motivation behind some of these posts.