Stress testing at least proved one thing: Even the blocks are all full, majority of users will not be affected. Blocksize should only be changed when there is a REAL problem, not by fear and imagination
Human are all adaptive, when banks closed during weekends, they don't change bank, but wait for it to open on Monday, and reduce their transaction frequency
That's all fine when you control all the software being changed, bitcoin network is a bit different and changes have to be planed way ahead, not when there's a problem, for everyone to upgrade, or at least a majority, it takes probably a year.