Have you seen any performance issues? In almost all cases the performance is the same as (well written) Java apps.
Maybe its not really a real performance issue, but I was inspired by:
I remember a long time ago that the syntax, like +=, was done because compilers at the time could be made more efficient.
So i did some tests. I wrote some code using sums and increments, first in a Java Lib, then in B4A, the results were really conclusive. Java code in the lib was faster than B4A (tested in large loops).
For example a simple code in java:
B4X:
int z;
z++;
B4X:
Dim z as Int
z = z + 1
Then just for curiosity tested
B4X:
Dim z as Int
z = z + "1"
So, maybe could be more room for a new set of asigment operations with a more specific and optimized behavior (for example avoiding the implicit type convertion, only working if the operands are the same data type.