During the last 4 years I bought an Omnia7, Lumia 800, LG E906, Lumia 920, Lumia 620, Lumia 820 and a Lumia 630. Actually the Lumia 535 has the worst touchscreen respectively touch recognition I've ever noticed using Windows Phones - by far! I had 5 different 535 (3 single SIM, 2 dual SIM) and all had the same issues with the touchscreen.
The "fixing updates" addressed the touch issue, but could not solve it completely. At least now one finger is registered fine most of the time. The result when using two fingers is much better than before the update, although every now and then there are randomly "ghost touches" happen and pinch to zoom only works, if the zooming fingers are not about to touch each other. Recording 3 or more fingers results in a lot of errors.
The update reduced those issues acceptably, but testing the screen with the multitouch test (windowsphone.com/en-us/store/app/multitouch-test/9fd32b5a-2f82-e011-986b-78e7d1fa76f8) app still reveals the matter people complaining about. It has nothing to do with trolling.
It is interesting, that the Archos 40 Cesium (archos.com/us/products/smartphones/cesium/archos_40cesium/index.html) has the same stuttering screen, if a finger has contact to it. It seems most likely that the snapdragon 200 could be the problem - even though the Lumia 530 runs not that bad with that SoC. It has very efficient and power saving multitasking, but a bad single core performance. The GPU ist bad, too, but that should only strike, if the tasks are extensive and the RAM interface with that 333Mhz 16 bit single channel LPDDR2 do not promise the unimaginable as well, but should be sufficient, too.
I would like to see WPCentral investigating. pls guys, start some digging! What is going in the wrong direction? Quality deviation during the production of the hardware parts? Low budget hardware? Failure by design? Aggressive power saving in WP 8.1, that is not suitable for that kind of SoC?
Until now you could recommend any Windows Phone without any exception - that is history.