Do you mean accessibility? I did notice disappointing non-native-like behaviours when I tried typing in an AvaloniaUI textbox but I'm hopeful they will manage to solve that and other issues.
For example, pressing a space will always introduce a new item in the undo/redo history [0] which isn't how native textboxes work.
Eco probably means ecosystem, which I assume it means lack of UI Controls like Maps view, Graph/Charts for visualizing data, Date pickers and other stuff they you can get from vibrant UI ecosystem.
But I think some of this stuff is already handled in Avalonia ecosystem like https://github.com/Mapsui/Mapsui, https://github.com/beto-rodriguez/LiveCharts2 and few others...
