With all due respect - (1.)you are staying that Task Killers are not useful with Android. (2.)My argument is that running fewer apps leads to better performance and that Task Killers are an efficient way to kill tasks if you set the ignore list up properly. I ran a benchmark as part of my education process and want to share the results. It speaks directly to the premise - my phone runs 30% faster if I kill apps.
1.) No. Again another logical fallacy. Straw Man this time. (sorry, don't recall the Latin for that one). I in fact have admitted that task killers can be useful. What I am stating is that they are not necessary as a routine maintenance app. That regularly killing processes is not beneficial and can be detrimental.
Let me explain it this way. You are an executive of a company and you hire a traffic manager whose job is to make sure employees can get to work and leave as efficiently as possible, but you only have one guarded gate and limited parking near the office. There is, however a large parking lot adjacent to the office outside the gate. The traffic manager is paid a toll by the cars passing through the gate. In this analogy you are the Phone owner, the "traffic manager" is Android's process management, the "employees" are apps, the "gate" is the CPU and the parking lot is memory. The traffic manager's compensation is battery power.
Normal operations mean an employee arrives and is processed through the gate. They park near their office. As more employees arrive, the internal lot fills up and your traffic manager decides who should be moved outside to the adjacent lot to make room for the busiest workers. Since they must go through the gate, there is a fee.
You call down from your executive suite and tell the traffic manager to clear the parking lot because you think employees can do their jobs faster if they have unrestricted access in the internal lot. He wastes time moving all the cars to the external lot and collects his toll (uses battery power.)
Now you call for a new employee, we'll call him Peter, to get working and he arrives unrestricted and zips right into the first slot he sees. He calls the traffic manager and says "Hey, for me to do my job, I need Bob from accounting working." So the Traffic manager goes and get's Bob, even though you had him moved a few minutes earlier. Bob calls down and says Mary in HR makes his job run smoothly so The manager goes and gets Mary.
After a few minutes you look out your window and see the cars in the lots and call down to the Traffic manager and tell him to clear the lot again. Now, if Peter wants to continue working, Bob and Mary must come back but Bob can't get in because Mary is still leaving. Then she must turn around and come back in.
Can Peter get to his job faster? Sure. Can he get his job done efficiently while you are shuttling the other employees around? Probably not as well as if you'd left the Traffic manager alone to do his job. Is there a negative impact? Absolutely. Not only is the operation of the company less efficient, but the traffic budget (battery power) is depleted prematurely.
Now, as a company executive would you award Peter from being the fastest guy to his job even though he wasn't the fastest guy at his job? And would you blame the Traffic manager for being inefficient because he did what you told him to do?
2.) Without knowing what you are killing and what you use on a regular basis, I cannot comment one way or another on why you see the results you do. Although, if we are going by your benchmark numbers, that's only a 20% increase.