So far his biggest negatives seem to be a) immigration mushyness b) lousy debater c) inelegant stumbling onto the national stage, which is also b) but that’s the thing.
As a guy who’s watched him for 12 years my political attitude has been “He would do mostly, say 95% of the time, what I’d want him to do, so I’m ok with this.  I am just not concerned about “what would he do?”  I was also concerned about the rest of the country goin “Texas again.”  No need to rehash that.
I also said his negatives are relatively small ones, Tardasil, the Trans Texas Corridor thing (which really hasn’t been a factor at all in these debates), “cronyism”, and that he’s an Aggie.
I’m an idiot from Texas, so I misunderestimated expectations I think.  I’ll cop right now, his debate performances have been underwhelming.  I could cry about the debate format, but that’s bullshit because others (Mitt comes to mind) seem to handle it just fine.  He’s had a couple of good moments and a buttload of not-good moments.
My thoughts at this point are not to excuse his flops. They were flops. I’m more focused on two points:
a.  Can this guy sell it to the electorate at large?
b.  Does he distinguish himself to the base, who seemed largely frustrated with the pool of choices prior to his entry into the campaign?
c.  Can he beat Obama?
d.  No one expects the Spanish Inquisition, oh bugger, ok three points.
I still don’t think he’s even close to settling point a), but I don’t think that’s the main objective of a primary (it most certainly is a secondary objective).  Those of us who watch pols negotiate themselves through this murky mess are looking for someone we can get behind.  That’s the deal.  At this point in 2007 I think the top two guys were teh Fred and Rudy.
We ended up with McLame.
On point b) I think he’s largely gotten past the Tardisil criticisms (thanks Michele for the crazystupid!), he’s answered poorly on immigration (which got sighted in on “resident tuition rates for illegals”), using stupid language to defend the 2001 legislation.  I’m won’t defend it with “it’s a border state thing baby, you wouldn’t understand”, he’s just done a poor job defending the position and that’s plain to see.
And he’s come across poorly as a debater.  We watched em, I don’t have to recap that either.  He just has.
A primary fight is:  Who could win?  Who should win?
Two different questions.
I think he could win.  Should win is up to him.  Ace mentioned somewhere today, not sure where, that Perry apologists do him no favor by excusing poor performance, or muddled responses, he needs a wake up call.  I agree with that.
I’m confident that he can govern as President the way I’d want a President to govern.  He’ll go after the EPA, Obamacare, taxes, drilling in the Gulf, over-regulation, intrusive Federal government.  All that stuff I care about a lot.
He still has to make the case that he should be leading the charge.  Because there are an awful lot of conservatives out there, who he needs to convince. He hasn’t done that.
I do think he could. But it’s on him to do it.