Current tools translate MOV EAX, [EBX+4] into variable = pointer[1]. A better tool would recognize the PureBasic runtime library (RTL). It should spot PB_StringBase and automatically convert ASM patterns back to Left(), Mid(), or Trim().
The most significant improvement possible is the application of Function Library Identification.
Even a "better" PureBasic decompiler cannot recover original variable names (unless debug info is left in). It cannot reconstruct macros. It will always produce a "lossy" output—functionally equivalent but stylistically different.
However, functionally equivalent is the bar for "better." If the decompiled code can be recompiled with PB v6.10 and behave identically to the original (minus variable names), the tool has succeeded.
Since no single "better decompiler" exists yet, professionals use a multi-stage process. If you are trying to recover a lost source, here is the current optimal strategy, which is better than using a broken standalone tool.