More rationale about the call stack depth check

EIPS/eip-7069.md

@@ -119,7 +119,9 @@ We have changed the ruleset:
     - Ensure that at least `MIN_RETAINED_GAS` gas is retained prior to executing the callee,
     - Ensure that at least `MIN_CALLEE_GAS` gas is available to the callee.
 
-Removing the call stack depth check was initially considered, but this would be incompatible with the original `*CALL` instructions, as well as `CREATE*` instructions, which can be intertwined with the new `EXT*CALL` instructions in the call stack.
+Removing the call stack depth check was initially considered, but this would be incompatible with the original `*CALL` instructions, as well as `CREATE*` instructions, which can be intertwined with the new `EXT*CALL` instructions in the call stack. As such, keepeing the call stack depth involves the least change for legacy code.
+
+Also, we find the simple (as opposed to a complex 63/64th rule) hard cap reassuring that the call stack depth won't explode after gaming the gas rules. Lastly, the amount of gas to reach depth of 1024 is huge, but not absurdly huge and we want to avoid constraining the schedule by relying on current order of magnitude of gas limits.
 
 ### Output buffers