At first viewing, I like the proposed changes. They make sense to me.
I already had house rules for using XP to buy Talents and Spells without increasing IQ.
They were not used much as most players prefered to increase stats.
Using a staff as a ST battery is a very useful enhancement and should encourage Wizards to take the Staff spell. :)
I am less sure about the 40 AP limit for characters. The only time we had a PC with 40+ AP the player was a pain in the arse so I am biased!
Have fun and play nice,
Chris Nicole