Yes, in party-list PR it would be good to allow us to vote for 2 parties…our favorite (but maybe not seat-winnable), & a seat-winnable party we like.
I prefer that. But it would be regarded as a complication. Anyway tradition wanted to discourage small parties. The option to vote for two parties would be rejected as a complication.
For a first PR proposal, just propose ordinary list-PR, like 2/3 of the world’s countries use.
Later we can propose the 2-party option.