If we have Foresight as our 9th level spell that's prepared and we decide we that need a Fireball that is already prepared at 3rd level we can still upcast it to 9th level in this new system, right?
It can be very good depending on the DM's discretion since it's all in his hands according to the text. A lenient DM that puts the point in the PC's favor most of the time then it's fantastic. :)
Can you fail your Reach Beyond roll on purpose? Sometimes you might want to take the risk of something bad happening if you're desperate to cast a certain spell.