Okej so dropped it to 9 mb by not building it with Crosswalk but just Android. Not sure why one wants to build with crosswalk then in the first place? Everything is working accordingly and I even have a slight performance increase.
Crosswalk has better performance on lower versions of Android (less than 5 Lolipop), that is 4.x. Android 5 has good enough WebView that Crosswalk is usually not required. But if you want to support older versions*, too, I think you can't get a good performance without Crosswalk.
*this is the main problem for me on Android. First, Google makes the OS. Then the device company edits it. After that, your carrier adds some things. After all these steps, you receive the OS update, which could actually be already more than a year old. It is also limited to a country, it takes different time to come to a different country.
But if your tests show that everything works fine without Crosswalk, then you can probably build without it.