VTE isn't particularly fast or lightweight either way.
The developers also see it as being GNOME Terminal as a widget rather than a library. Leads to hard-wiring only what GNOME Terminal wants and not providing a way to do things another way. Many arbitrarily private APIs, etc.
I had a project providing a keyboard-centric terminal using VTE and we could never get them to expose the APIs we needed for keyboard-based text selection, etc. Handed it off to other people but they lost interest too, largely because it's so frustrating dealing with VTE.
Needing to have a fork of the library and repeatedly porting forward patches to expose APIs for pausing/resuming output, text selection, etc. was frustrating. Kept needing to patch it to add new APIs and work around problems in it. Haven't really kept track of new alternatives.
Definitely won't be working on something like that again but it would be nice if there was another terminal picking up the same features (Vim-style mode for text selection and a Vimperator-inspired URL hint mode displaying numbers over them and allowing quickly opening one).
Way too busy with other things that interest me far more and I simply don't care as much about having efficient ways to do things with the keyboard now that I no longer make any significant use of a laptop. Still burned from dealing with VTE and other GNOME-adjacent things too.