As I understand your meaning, "too much quality" = "extraneous features" (extra, unwanted features) Preferred version - "Why don't we remove extraneous features to reduce cost?" Other versions - "Why don't we reduce functionality to the bare minimum to reduce cost?" "Why don't we limit the functionality to the required features to reduce cost?"

Both are fine, so that's good news. Your point is clear either way. The context and more subtle tone is what we are looking at here. "Excessive" sounds smarter, for lack of a better word. In a business meeting, you might stick with this word. However, if you have discussed this topic a number of times "too much quality" could work. It makes you sound more frustrated. It is a little counter-intuitive though, so I'd be careful with it. I only mention it here to note that both make complete sense; it's merely that "too much quality" sounds a little like the country song....."it's like a girl too pretty with too much class, being too lucky or a car too fast." One would typically think, the more quality, the better. Excessive has basically tells the hearer "this is too much."