Do you Californians really hate Arnold that much? There are a number of things I disagree with him on, but I enormously respect him as a politician. Frankly I think the California political system has so many structural problems built into it (such as a supermajority vote required for tax increases) that the greatest politician in the world can't solve your problems on his/her own.
It seems a stupid move to me to say Whitman is the same as Arnold-it vastly boosts her weak stock.
I think you have some good points, but there are at least a couple counterpoints.
One is that the exaggerated points Arnold made (e.g., I am rich and paid for my campaign and own no one - and then going on to take more special interest money than the guy he replaced he was implicitly criticizing) - apply to Whitman too, it reminds people these talking points sound good but can be false.
A second is that when the voters are highly anti-incumbent and dissatisfied with how it's going, this can be good politics.
Either Whitman is going to tar Brown as 'incumbent career politician' and take advantage, or Brown is going to at least counter that with 'Whitman is just like the incumbent'.
It also exposes how much her campaign is a cookie cutter campaign consultant bought and paid for "parrot these phrases" type campaign to expose her as a 'phony'.
This in turn plays to Brown's advantage as a thoughtful politician, right or wrong, who doesn't say the consultant-directed phrases.
On your point about the 2/3 budget vote, let's hope voters do the right thing and repeal it, IMO it's the most important ballot initiative (Yes on 25).