I guess I'm uncomfortable using taxes to pay for stuff (especially overfunding) that will be mostly crap. Taxes, because if you don't pay for them, you go to jail, should be subject to a particularly strong level of accountability[0], and "we don't know what is going to be useful" is just really a recipe for spending abuse.
Peer review is one thing (and it looks like it's going to be getting better)... But reviews for funding - that's really tricky. How do you select whom to review science? In our current system, you wind up with program administrators (people who advocate and shepherd funding projects) who are mostly[1] people who 'couldn't make it in science'. So you get effectively second-rate-intelligence fanboys and fangirls who get paid six figures to fawn over the scientists with the biggest mouths and most outlandish claims. To actually conduct the reviews, typically PIs are hired (in a secreted process[2]), so there's of course a level of cronyism involved - not to mention how PIs are generally clueless for other structural reasons. It is hard to believe that this system is efficient or effective at being a good steward of the public trust.
[0] Science is not by far the worst area where government excels at failing to be accountable, but I also see no reason to increase our investment in a system that isn't working.
[1] I know one program administrator who isn't incomptent, she's my ex-boss; the reasons why she wound up as a program administrator are rather complicated and everyone hates her because she isn't interested in doing things the usual way. My neighbor growing up - who introduced me to science - was a physics administrator was probably also not incompetent, but I don't really know.
[2] by which I mean the process is not secret, but the actual goings on are, i.e. you don't know who reviewed you etc.