The thing I see over and over here, Chrome. It really is not the fastest or most responsive browser. I use it mostly because it renders everything correctly. Killing it or using greenify solves the problem for me. I am using temaseks from with Yank555 kernel and I have absolutely no lag issues at all.
One has to have a look at how your device is being used. If you have a whole bunch of apps, including games installed, remember that even when killed, they still tend to run in the background consuming memory. This is not always evident, especially after a clean boot. Use a tool like ES Task Manager and have a look at how many user apps insist on starting up. Apps like YouTube run at startup and if you don't constantly use it, turn it off. I even stop some system apps like Voice Dialer from starting up, since I am not using it at all, I don't see the need for it to run at start up.
There are many ways to to improve performance, even with "limited" ram. How your device performs depends entirely on how you use it.
As for the animations, it is not a placebo effect. The ability to have lower/disable them under Developer options makes a huge difference since it was introduced to reduce lag when debugging an application.