I would agree with term limits for the PM.    With regard to 1) - the Prime Minister is actually selected by the party in power.    The PM is just another MP when you get right down to it, and becomes leader at the Party's convention.   So not sure how your #1 would be implemented.     It is up to the party members to decide who leads their party.

3) would guarantee that our perpetual election cycle gets even worse.   

4) Definitely agree

5) Another one that would be hard to enforce and harder to police.    The In and Out Scam was about this type of thing (except in reverse - it was about spending Federally vs at the Constituent level).       

I would add that Political donations should NOT given any tax credits.