doc: Update readme with disclaimer

Author: matzehuels

README.md

@@ -15,6 +15,8 @@ Inspired by [XKCD #2347](https://xkcd.com/2347/), Stacktower renders dependency
 
 📖 **[Read the full story at stacktower.io](https://www.stacktower.io)**
 
+> ⚠️ **Note:** The ordering algorithms are still experimental and may not produce nicely stacked towers for projects with a large number of dependencies. Results can vary. We're actively working on improvements.
+
 ## Installation
 
 ### Homebrew (macOS/Linux)