I don't think you understand how software engineering works if you think all that is required is changing a number. I guarantee the backend for LoL isn't written in an interpreted language like Perl. It is probably a combination of Java and C/C++. Both of these languages are compiled (I am aware Java emits byte code and C/C++ emits machine code).
On the C/C++ side (assuming use of gcc), changing a single number with high enough optimization level can actually have a significant changes to the emitted machine code (I'm not sure the level where this happens, high level optimizations have really strange effects on your applications behavior as you go past 3, and 3 itself isn't always a safe choice). I truly hope LoL isn't run with anything great than -O2 (-O3 and above can actually disable explicit memory corruption protections in the name of performance, creating security vulnerabilities).
It can also have unintended consequences elsewhere in code for a codebase that suffers from severe technical debt (the boards likes to refer to this as spaghetti code, but that is not entirely accurate; spaghetti code is a type of technical debt).
Now, if champion numbers were stored externally such as in a relational database or a config file there wouldn't even need to be a code change. However, in C/C++ there are performance gains to be had by hardcoding numeric values as the compiler can make better optimization decisions. The config file approach gets complicated for large scale distributed systems, which may require repackaging the backend (which, depending on tooling, may require a rebuild of the software) if something like Puppet isn't being used to manage configuration. The database approach has complications depending on replication schemes and colocation considerations.
I'm going to stop going down this rabbit hole now.
http://i.imgur.com/23fX9dd.png&noredirect