Totally agree; Windows Text for normal human voices is pretty bad. There is support for both google text-to-speech (better) and ElevenLabs (much better) but it is hard to setup in the current release. The next will be much better (maybe this weekend); I've added a configuration panel for setting the elevenlabs api key (they allow for a large amount of text-to-speech each month on a free account). You will also be able to set the default engine to use for unknown voices both for NPC and players.
For NPCs it is easy because they are repetitive and easy to cache to disk. So a high quality voice is easy to justify. For players the cache is rarely useful and a little creepy, so I disabled it. I'm cheap-as-hell, so I'm making it easy to use Windows TTS for players (because it is free and fast) while using the slivers of pennies high quality services for NPCs.
One case where Windows TTS is more than fine -- Clockwork. If anything it is not robotic enough, so I'm wrapping it in vocoder effects. It's pretty good. Oh, I can attach.. a work in progress, but here are "Prototype Oscillator" and a Vahzilok "Reaper"; I'm reasonably happy with both these.
95c4f_Pieceremov.mp3
b7fc7_Itsalwayse.mp3