I guess it boils down to your view on house rules. Are you a RAW warrior?
lol. Not even a little. I have changed things all of the time, for ages.
If your sorcerer player had an idea outside the box on the list, there's the spell list p. 209. And why? Because...they certainly don't warrant altering the class mechanics or spell selection to accommodate.
Right. THe player's choice was to be a sorcerer. You get the sorcerer stuff. You don't say "I want to be a sorcerer...but I want it this way and I want that too...and this over here -because concept."
You say it yourself below, it's about the toolbox.
It is not wrong to think that way. It is just different than I do. I do not say here is the tool box build within the constraints only. I would say here is the tool box and look I added on this little side pouch and the tools in there are very cool too. Build your vision, that is cool.
Whereas I see the whole point of HAVING the toolbox is to work within its constraints. By all means, get creative! I don't want to play "make believe" with unimaginative people. Think outside the box as much as you want...then work with what you have
in the box to make it happen. If that means to get closest to the concept you want maybe a sorcerer isn't the best option for a class, then do that.
For me, Houserules are like porn. I know what needs 'em when I see it..and the sorcerer spell list just isn't one of those things.
If you choose to be a sorcerer, then be a sorcerer. Don't say "I have to be a sorcerer ...but I want it
this way."
And IF such a fresh can of "bend the rules for meeee" worms is opened for some reason, you can bet your bottom copper piece the DM [me] is taking those worms and throwing them all over the damned place. So do be careful what you wish for.
The sorcerer is a limited version of the wizard with a few add on things. Thematically the sorcerer is unique and does have a lot of rich theme. Mechanically it is just as good as a blaster wizard and avoids all of the other stuff a wizard could do.
<space added by me for added clarity>
For me, this reinforces the idea, why not allow sorcerers to learn any spell.
Where for me, that does not logically follow at all. "Sorcerers are xyz...So it reinforces the idea, why not let Sorcerers be a-w?"
When I play D&D, I almost exclusively play wizards. This edition has tempted me to break the mold. We are still in our Age of Worms 3e game but when we play 5e and if I do not DM I will certainly play a wizard again. Tempted... but not duped. Sorcerer is second class again in this edition by RAW.
<emphasis mine.>
Right. Sooooo letting them choose any spells they want is what...pity?