Currently this is the best sheet out there. Some suggestions for the spell section:
1) Too much space is given over to Level, which is just going to be a number from 0-9, and also to Casting Time. Given how cramped the other columns are going to be with long spell names like "Protection from Evil and Good", I would suggest narrowing the columns for Level and Casting Time (where abbreviations are more easily standardized than for names and notes, e.g. 1 min, A, BA, ReA, etc.).
2a) Adding an additional spell sheet. It would just be a duplicate of the current sheet 2 with nothing but spells on it. The current spell sheet doesn't even have enough space for a max level Wizard to write all their core prepared spells and cantrips (to say nothing of additional always-prepared spells from feats and features). Another sheet that could be printed as many times as needed would resolve this.
2b) Contingent upon the above, adding a prepared spell indicator for spells, instead of titling the section "Prepared Spells". It would be faster and easier to fill the Prepared Spell pip than to completely rewrite the spell list every time you change spell preparations.