AbigailII: Aargh, I would never be able to play giant Logic with colours, whatever the colours chosen :-)
But yes, an alternate piece set would be nice ! Otherwise, something should be done about this grey colour. Orange would be OK if well half-way between yellow and red, green a bit more problematic for colour-blinds. A darker grey would probably do it for everybody.
Anyway, a set with letters or numbers would be great. There are probably people who are more colour-blind than me here.