These are allocations on the size of multi-billion dollars, it can not give anybody an idea "what sorts of equipment is being bought". And the information that the NSA employs tens of thousands of employees is likewise useless.
You might be surprised what an intelligence agency can tell you about your country based off of those "larger" indicators. Especially when tied to other data points. Knowing what another state is capable of is by far the most important part of intelligence gathering.
The DIA has models to determine food supplies in China based off of the number of farm tractors and price fluctuations of dog food in the USA. It amazing how accurate they are considering the data points.
Really isn't a question of whether the information is a security risk or not. It is a question of freedom vs security.
Planes that cost in the billions? Equipment for the government is never cheap, mostly because they can't get economies of scale pricing. And not to mention that year-to-year changes can give you excellent information too. For example: say last year they spent $10b, and this year they spent $20b -- holy crap they clearly expanded something or bought some crazy expensive gear.
It's an intelligence agency. Most of what they do should be classified.
Here's a thought. We don't need them and they do much more harm than good. They didn't protect us against 9/11, mislead us into Iraq, took 10 years to capture Osama Bin Laden, didn't foresee the collapse of the Soviet Union, and now are mucking about with Syrian "rebels" (and indirectly supporting Al-Qaeda) fomenting the start of WWIII.
If they just didn't exist we would all be safer and we'd get to keep more money. By falsely leading us into war in Iraq for absolutely nothing, they effectively cost the US over $10^12. The cost of the CIA and other agencies is much higher than their yearly cost. They can't even manage their sys admins, why should we trusting them so much?
No, this should obviously not be classified.