>> What exactly is 'slower'? Compiling, or compiled code? The former, is 
>> less
>> of an issue unless doing image reworks. (Installing veiny packages, 
>> for
>> example)
>
> Its actually much bigger than that, although that's probably a big 
> enough
> issue by itself.
>
> If you change (add and/or remove) an instance variable in a class, it
> recompiles all the methods in that class and all the subclasses. For
> complex class hierarchies, that can take a long time even with the fast
> compiler. I can't imagine this taking 3x longer...

But with the possibility that I explained (late binding of method 
compilation)
then you will only compile the methods when you call them and only once 
at that time.

Stef