I am running a Dungeons and Dragons 5th Edition campaign for my family, and they will shortly be reaching 3rd level. My (8-year-old) son is playing a Sorcerer, and so will gain access to Metamagic options.
Both because it's more forgiving generally, and also in acknowledgement that my players are inexperienced and (in my kids' case) young, I'm largely in favour of rules that let them change out any options that aren't working well for them. I'm already using the November 2019 Unearthed Arcana "Class Features", which e.g. lets Clerics switch out a Cantrip on levelling, lets other (non-Wizard) spellcasters change one known spell after a long rest, lets martial classes change Fighting Style on levelling, and lets all classes change a proficiency along with their ASI.
However, the UA doesn't allow Sorcerers to switch out Metamagic options, and I wonder if this is deliberate. Is it likely to cause problems to allow the Sorcerer to change their two selected Metamagic options after a long rest, or alternatively on level up?