Biggest limitation in the free version for me, as somebody who likes to tinker with old games as a pastime, is that it does not support any other instruction set than x86/x64 and not many executable formats either.
There are a lot of good and interesting games that were made in the DOS era for PCs which used the DOS4GW DOS extender, and their binaries come in the OS/2 executable format (LE/LX) which is unsupported in IDA's free version. A lot of good and interesting games also happen to run on game consoles which use non-x86 processors.
Ghidra probably won't have plugins to support all of these weird old legacy formats and CPUs which the full IDA package does for a while, but hopefully it'll get there eventually. If it doesn't seem too difficult, I might even try creating a LE loader for it myself.
