The problem I see with that is, if you only look at the for loop (without the define statements), then it looks like Lobj, Obx etc. are simple variables. There is no way to tell what any code does anymore, unless the code editor has good color coding and you're not color blind.
So it might make writing code quicker. But it will make reading code more difficult.
So in my opinion, a language change that would make your example more efficient would rather be a foreach iterator. Not that I'm expecting anything like that in Fuze, but it could look something like this:
foreach var o in objects loop
o.x += 1
o.y = cos(o.x)
o.size = o.x * o.y
repeat
By such a change, it's still clear from looking at the code, what is supposed to happen, and you don't need to think about the type of collection you're iterating over. In case of Fuze, there are only arrays, so in my opinion, a change like this doesn't need a high priority :)