Alright, I'm gunna have to call you out here. Everyone else who thinks putting any points into q is worth it, too.
First of all, M7 just means you player her a lot.
Q gets 15% ad ratio every rank you add to it. Unless you're actually facing a pure tank character like maokai, you will most likely never get more than two of these off in a single fight. How much flat AD or on-hit effects are you building to possible justify that pitiful amount of damage and those two extra on-hits? Fight's over long before that's relevant.
You should never be using q more than once against the chickens or wolves. The big krug and the single-enemy camps are the only ones where that becomes relevant. The AoE of W, E, and Tiamat is more than enough to instantly clear most camps past level 4. By the time putting points into it allows you to Q multiple times, it's irrelevant. Why would you need faster Q's when one alone does the job?
The only point that's actually valid is strong objective control, where you do actually endlessly attack and proc q multiple times. But, are you really going to max an ability just for that when it happens so infrequently and you can live without?
This sort of over-thinking is what makes me question people. E base damage is aoe, lowers the cooldown, and is generally much stronger in more situations. If you start at blue or red, it's the first ability you should take, and Q has the least priority. Maxing it first gives you an overall faster clear on the many-monster camps, followed by W for more AoE base damage. It's an obvious go-to that is almost always the right way to do it, not just "because that's the way it's done."