Three commercial controls plus three infos is exactly what I had on my 200 that I ran for the first time last year, and I had no complaints about that. Here in Kent, it's nigh on impossible to devise a valid 200km route with no info controls at all, and I've abandoned many routes at the early planning stage because they would require too many info controls (in my opinion).
That said, I've done 200s with considerably more infos and they haven't ruined the ride for me. It's a balancing act - it's preferable to avoid info controls if possible, but if you have a nice 200km route that's worth riding, you don't want to mess about with it too much just to make it work without infos or you might end up losing what makes the route worth riding, especially if that means adding lots of over-distance.
The main thing for me is that info questions need to be straightforward and easy to answer - they're not meant to be a test of intellect. Anything that requires doing maths or stopping and searching for a sign is a no-no for me. Colours are to be avoided if possible, for the reasons others have mentioned.
For me, the best info controls are the ones where you can see the answer while riding and it's memorable enough that you don't have to stop to write it down until you get to the next full control (another option is to record the answer on your phone as a voice memo).
I amused myself on my 200 by having *exactly* the same question for each of my three infos. It's just a shame that I probably won't be able to do the same when I run it again this year.