That isn't the job of a producer or manager. Maybe quality assurance or testing? It sounds like you were micromanaging them.
If I were in that position I would try to educate them about what makes a game hard and how hard games should be. I would educate them about typography. I would not tell them what to do. They must find the solution themselves.
Hm, I'm violating my own advice with the paragraph above. :)
As a developer, I hate it when somebody gives me too vague problems "game is too hard" or too detailed assignments like "make the font size bigger". I need an accurate problem description with all requirements. If it isn't accurate, my solution will probably miss the point. If I haven't all requirements I will probably violate some of the unspoken rules.
We were a bit more specific than 'make it easier', I just have a vague memory exactly what we said because it was 8 years ago and a lot has happened since then.
And we were a super small company. I had to wear many hats; overseeing QA was one of them.
Micro-managing is an extreme term, and I don't think we were. We weren't telling each developer what their tasks were for the day, we were communicating with their project manager and saying which bugs or features had what priority, and by the way we played the build and we think the font looks too small, could you please increase the size, it's okay if the UI takes more space, please remember not everyone will be playing this on HD tvs, thank you.
And I was playing each build to do some internal verification that the bugs they say they fixed did get fixed, yes. Personally I think it's better the publisher knows what's going on with their own game (keep in mind, the developer didn't pitch the game, they were hired) than blindly trust that everything is going the right direction, until it's time for a milestone payment and "holy shit, that's nothing like what we asked for! you don't get paid until it's fixed!"
Half the time I spent as a producer I was worried about the fact that I wasn't doing any programming, and my skills were atrophying.
Production had some real perks in comparison, being able to meet a lot of people I admired, going on business trips, etc, but I got frustrated with only trying to cajole developers to add certain features that I thought would make the game better, instead of being able to dive into the code and add the feature myself, and iterate until all the kinks came out of it.
You'd be surprised how many times you can say "this game is too hard, you have to make it easier" or "the text in this UI is too small, you need to make it easier to read" and developers still won't do it, or will only tweak it marginally to say they did it, instead of sitting down and actually trying to make the game easier.
And then the game comes out, and it gets blasted by critics for being "too damn hard".
If I were in that position today I'd be a lot more specific, but I can only iterate when they give me a new build, which usually takes days. I can't change a variable and rebuild it in 30 seconds like I could as a developer.