It just depends what your tools are written in and what you are most comfortable with. My tools are mostly all in C++, so I'll be using the
scripting language to add scripting support to my projects. Lua is more C oriented so if you know C/C++, it's pretty easy to pickup. It's similar to PHP in a sense too.
With well design tools though, you can use anything really. I'm working on rewriting my lightweight generic Silkroad proxy that runs in C++ and will take care of all the security stuff and the login/world server transition packets. With that program, you can use any language to write a clientless program as long as it supports sockets. I've already made test programs in C#, Autoit, and C++ and a friend has used VB.net and Java to test it. It's really simple and easy to use and will allow development to be more less complicated in other languages. That is what you are after really, 1-2 combos of "smart" programs.
For the more heavyweight version which will support plugins and whatnot, I'll be using Lua to interface user scripts with the system. However, I might also check out
as well since it's supposed to offer some good features as well. I've not really learned the language, but it comes highly recommended and a lot of games use it as well.
So, client modification based tools are best done in C/C++/ASM for an injected DLL, if you just want to write client patches anything that can use Win32 API is fine. For network based proxies, anything works, but higher level languages offer solutions that require less code. For scripting, take a look into Lua and Python. For utilities, any .Net based language will work really nicely due to how big the library is. Autoit does has its uses, but unless you are writing pixel bots or tasks to automate keystrokes, I'd not try to use it for packet based stuff.
The key is not as much as "theoretical performance" but rather "practical implementation". I've been looking at C#/VB.net lately and the .net framework has so much available to make life easier, you'd be crazy not to take advantage of it. However, some tasks aren't suited for it, so you just have to pick the right tools for the job. Low level stuff you stick to C/C++/ASM and then write anything else in higher level languages that speed up development and make life easier.
InvincibleNoOB also brings up some important points. If you are going to invest your time and effort into this stuff, might as well do it right! There is no real reason to rush anything in the Silkroad development sphere nowadays. Take your time and look around to see what you can do differently. If you don't, you'll just have yet another program for Silkroad that will come and go and no one really cares about. Just remember be creative and experiment!
