I can see SPS token easily over $2 as your $1 is a pretty conservative view...
I don't think that Chaos Legion cards will be much better than Untamed or any other previous edition cards, which make them comparable with those packs... So, $4 per pack + VOUCHER value - SPS discount (paying with tokens)... I see SPS and VOUCHERs very valuable in the first 1-2 weeks, or even longer... Agree with your "prediction" about VOUCHER value...
And don't forget the power of FOMO :) :)