Several comments on the idea.properties и vmoptions:
editor.zero.latency.typing=true doesn't have any positive influence
idea.max.intellisense.filesize increases the size of the files where the inspections run, so potentially it may decrease performance
idea.cycle.buffer.size increases the size of the console being saved, potentially it may decrease performance
Too big memory size indicated in vmoptions may be not suitable for everyone.
Also, there are many options that are enabled by default, for example:
-XX:+OptimizeStringConcat
-XX:+DoEscapeAnalysis
-XX:+TraceClassUnloading
or those options that aren't included in Java 8, for example:
-XX:+UseSplitVerifier
-XX:+UseStringCache
-Dide.no.platform.update=true - if a user doesn't use ToolBox, he/she won't get updates with this option.
-XX:+AggressiveOpts, -XX:+OptimizeStringConcat- may positively influence the performance
