Disclaimer: I have never been on a grant committee myself.<p>I see two problems with grant committees. 
1. Some of us are more theorists, others - engineers. Some of us want to solve mysteries, others - practical problems.<p>Which means that if the panel is composed primarily out of theorists then applications possibly yielding highly cited papers (solving general problems vs specific) are more likely to get funded. This also creates incentive to split the work up into as many papers as possible.<p>Likewise, panel composed primarily out of engineers is likely to undervalue deep problem research without physical deliverables. I have absolutely zero idea how to adjust for both these cases, though.<p>2. Another problem is relevance&#x2F;urgency. Some problems&#x2F;proposals are always actual and can be polished and reapplied every year. Others can quickly get practically irrelevant or competing technology become <i>de facto</i> standard. E.g. analogue television (terrestrial), Magnetic Cassette (solve practical problems why those got phased out). Do we rank ones over the others or keep them in the same pool? I have no idea.