I just checked the tables ... You really really sure you want a wizard able to cast a time stop every time you do a goblin encounter?
(An average level 20 wizard has an intelligence score of 38 which according to the table you posted... Will have the ability to cast 11 level 9 spells /day 13 level 8 spells /day and 14 level 7 spells /day.... And so on) instead of his normal 5 level 9
Giving the wizards the ability to cast so many spells will serious make the game imbalanced. Wizard is already the strongest class in dnd it does not need more buffing
plus will make many meta magic item creation feats totally useless... A wizard that wants to cast more fireballs just creates wand of fireballs...
Not to mention that if you go on epic spell casting rules this is totally ...
(The level 80 D&D warrior goes to ice crown to fight the lich king. Level 80 warrior hits the lich king for 54000 hp damage. Lich king gets angry and retaliates for 50000 hp damage warrior dies.
The level 80 D&D wizard goes to icecrown to fight the lich king, cast a spell and hits lich king for 48billions hp lich king dies 47 billion and 900 millions hp overkill. The frustrated DM says the planet explodes and you die in the explosion. Calmly the wizard answers: yes but this wasn't me that was my simulacrum. I am in the astral plane, in my tower, taking a snack oblivious to the explosion. )
The spell bonuses are as stated in this thread. They do not go any higher than what is stated. IF you have a intelligence score of 30 or 35 you will only get the max bonuses as that of a 25 intelligence. I know as spell casters get higher levels they can get to the point of thinking they are gods.
Death:
If a player is at 0 hit points they are unconscious. They will not be able to do any action at all.
If a player falls below 0 in the -1 to -9 range they are unconscious and usually bleeding out. IF someone does not bind their wounds or attend to them such as a healing spell they will become dead when they hit -10. They will lose one hit point per melee round. Healing of any from -1 to -9 means ten points of healing per -1. A successful stabilize roll can help the person. Plus if someone has healing as a skill they can help a lot too.
At -10 hit points the character is dead. Only a few spells can bring this character back. Saving a hand a foot or the head you can always get a reincarnation spell.
I hope this explains my view of character death.