Thanks, I thought that might be the reason but was wondering if there was some legal requirement for the number of electorates or something.
Why does MMP require 120 MPs?
I always found the dis-enfranchising of voters a concern as well; but I also like that the Threshold exists. Otherwise there is a high chance we would have a plethora of smaller parties causing chaos.
Personally I would like to see a pseudo STV/MMP type of system where voters could rank their preferred parties and if their party doesn't make the threshold their next choice is utilised. STV could also be used for the electoral vote as well, but the important part for me would be that STV was used for the party vote.
Unfortunately if people are still confused about how MMP works, I doubt such a system would have much luck either.