Careful with that goal post. You initial said people didn't like it because they didn't want to think in their games, an insulting and frankly bad post.
As you your other points: spamming light attack and using quen give me the highest dps. I literally cannot kill things more efficiently; the animation time on signs and bombs lower my output. Have no need for stamina, rage works just fine. And yeah, I have the whirl attack. Now I can hold square instead of pushing it.
I don't care if you like the combat. I really don't. I do care when people do to drastic, insulting lengths to justify a system.
The goal post hasn't moved at all: the point of that post was to show that you hadn't thought much about the combat system given the alternatives to Quen. Everything I said was true for lower levels: someone who just relies on Quen all the time is not thinking about how the game works. Now that I know roughly what level you are and your spec, I can go into more detail about what I think you may have possibly missed in your testing. For higher levels, I will admit that my statement relies on theorycraft since it'll be another 20 hours before I get there but, given that you are still using light attacks rather than just whirling, I think that there are still other things you can do to boost your dps which you may want to reconsider since you have allegedly tested these.
It sounds like you are spamming an unbuffed Quen using adrenaline points which means that each Quen can only take a handful of hits before going down (1-2 hits in my lower level experience on Death March). Quen boosts your dps by allowing you to swing your sword in the time that you would have used to dodge. This may not, however, actually be a dps boost since dodging in the right direction often positions you behind or beside your opponent for bonus critical hits which, given that you've spec'ed for fast attacks, are huge sources of damage so you might want to dodge anyway even with Quen up to reposition, thus devaluing Quen. Sign alternatives that might actually boost dps are Aard which might give you an instant kill while guaranteeing you 1-3 sword hits with its AoE stagger, and Igni which also AoE staggers them for you to land 1-3 hits. This is especially true against humans who will parry most of your attacks, and you'll have to do 3-4 attacks just to break through their guard if you use Quen or wait for them to attack so that you can parry and counter which wastes time and Quen duration from getting hit unless you're dodging... in which case, you didn't need Quen anyway. With rage, you can even chain Aards together for 2-6 consecutive hits while staggering most of the enemies if you've positioned them right.
Concerning bombs, I think that you're underestimating the free attacks that they give you. For example, you could open with the Northern Wind bomb which freezes every enemy in a decent radius for 8 seconds (basic bomb) and gives you free attacks with bonus damage while they're frozen. When your target recovers (everyone else is still frozen), follow up with Aard to extend your combo for more unblockable damage or instant kills. Again, that's 2-6 connecting attacks in a row. You've probably already killed someone in your opening salvo. You can even throw Quen up before you enter combat and your stamina regens to full so that you have both Quen and another sign ready to go.
I'll admit again that I'm not high level and perhaps it all changes when you get there and you do end up killing things in 1-3 hits so a single Quen is actually pretty significant. If you can't kill them in one sword combo, however, it seems like there are much better alternatives for raising your damage than Quen and ignoring other signs and bombs completely. With other signs and bombs, you do end up with a quick and deadly Geralt who will slice a man down before anyone can respond.