Teirtex games had crap graphics on the ST also even if it used the full colour capacity of it, why would 16 clours more mean it would become better.
About Teque they did as i see good enhanched Amiga version compared to the ST... ok some might still use 16 colours on Amiga also but it could be because adding more would slowdown the game too much?
W.J.S is a very good gamecompany i don't know why you would mention it as a bad one? Any particular game you think of? ORK certainly looks much better on Amiga