Folks, Microsoft is officially considering providing Python support in Excel (finally). If you are interested in this, please visit their uservoice page and let them know what you think. Thank you!
Yes they should choose Python, and in the process decide if it will be Python with a .Net library (standard and core as seperate libs please!) or IronPython. This in itself is an important first choice.
Then it has to be done in a mechanism that enables the exact same libs and user written python code to work in the same way across all the Office products.
Other languages have been suggested, all good choices with their own merits. Lua is a good chocie for compactness and speed. C# is lingua franca of commercial developers so would suit ISVs but i think too heavy for end user scripting. Nim or even freepascal maybe? Lastly whatabout just using VB.net consistently? VB is a great language for newbs and casual/adhoc programmers .... but it gets ignored because of problems with consistency of implementation by MS.
Disclaimer: A huge fan and long time user of python here. I also spent largest part of working life in ISV world rather than end user land.