I am not sure this is something other engines even offered at this level, but my issue is bindings support.
3.X had (3rd-party) production-ready bindings, even for niche languages.
4.X, with hopes of improving support for compiled languages, has a new bindings system meaning that all bindings need to be redone as a new effort. This happened with the language that I'm interested in, the group that made the production-ready 3.X bindings abdicated the crown and there have been splintered efforts by individuals to work on 4.X bindings.
So it (3.X vs 4.X) is language vs engine features. When/if 4.X bindings do come out, it is not known how similar they will be so (aside from non-Godot-specific code) that will likely add complication to it as well.
I don't really care about consoles (needing to jump through hoops to develop for it is one reason) so a different potential issue would web export limitations. Both for different languages and for visual quality (AA). Those were issues in the past, though I'm not actually sure where they're at now (the 4.1 docs do say you can't have C# web exports in 4.X).