The knock thing is specially contentious, I think it is fair to make it specially bad for wizards, after all I do get the main points -He can prepare something different tomorrow and it isn't fair that a wizard can make a fellow party member superflous with just a few hours rest-, but again for sorcerers this isn't as clear cut, for a wizard preparing knock is a matter of adaptation for a given day, for a sorcerer is a life path choice -or at least a long term compromise-, a sorcerer doesn't pick knock to casually replace the rogue, a sorcerer picks it to be a magical thief, probably even hoping to do that in a permanent basis, and being extremely noisy each time goes against that. The only way I think both camps could be satisfied is by keeping knock as is and then provide sorcerers with a non-noisy version that cannot be ritual casted or have knock say that sorcerers don't produce the noise, I don't know.