The ritual part of your argument can be ignored as it has been debunked a few times already. Even a fighter can take ritual caster so imagine the sorcerer...
No, it cannot be ignored.
There have been
attempts to debunk it, pointing to the Ritual Caster feat, and they have been, frankly, dishonest.
For one, they ignore the Metamagic Adept feat.
For two (and this is the
really important part): They are lying about what Ritual Caster actually does.
Ritual Caster does not let you substitute for a wizard who has been adding ritual spells into their spellbook as they level. Ritual caster gives you
two, 1st level rituals.
That is it.
You don't get additional ones as you level. The only way that you can add to it is by finding scrolls or spellbooks and copying spells into you book, at a cost of time and money. - This should sound a little familiar to you, since it is exactly like what the wizard does, except the wizard does it
better. (Since they can actually scribe and cast from spell slots rather than just rituals.)
When comparing the wizard and sorceror, the wizard's ability to scribe additional spells isn't generally brought up, because it is DM fiat and so cannot be assumed.
So, to clarify for those people making the claim that a sorceror with the Ritual Caster feat is a fair comparison to a wizard without it:
Are you talking about comparing a sorceror with two 1st level rituals in their book to an nth-level wizard?
Or are you comparing a sorceror with an extensive collection of rituals through additional spells with a wizard that has
also had access to lots of additional spells?
Pick. Your. Hill.
As for the beginners. It is exactly for them that I fear that this rule is way over the top. Not all young DM will notice that the wizard never shine and that the sorcerer has all the spot light. Then they will wonder why no one is making wizards just as no one was making rangers. When they saw a beast ranger lauching his bear at an enemy an kept having his full attacks, using a bonus action only to redirect the bear to an other target they said it was not in the rule. I asked if they had lots of rangers in their games and replied no. And they understood why I had made the small changes I had made.
New players don't tend to perform an intricate cost/benefit analysis of classes, or have the knowledge about the game that allows them to do so. In the majority of games by new groups (often using official adventure paths), there is simply not going to be the downtime required to abuse this option, even if the players were able to find some telegraphing of future encounters.
I fully accept that your particular game, because of its several unusual factors, may suffer from this rule, and so it would be better not to use it in that case.
It is the rather hyperbolic insistence that it will break D&D as a whole that I find objectionable.