Re: Virtual cards and Errata cards
If they were created - is there any reason why they cant be released in Beta form for everyone to play test over the course of a month or more - all the time getting feedback on the forums. Feedback would include players feelings about the cards, but more importantly identify issues with the cards. This process would need to be repeated for cards that the community are not satisfied with.
During this time they would not be tournament legal.
This would involve the whole community in the process and negate the need for a playtesting team. A design team would still need to modify the cards as required.
Steps for Errata
1) Community identifies cards needing errata (via forum) - this needs to be a permanent forum where the community notifies current and future problems and a judge will need to decide if they really do need errata.
2) Design team create modified game text on selected cards.
3) Release beta version for play testing.
4) Community comments on card in general and problems encountered (via forum).
5) Design team redesign cards that encountered notable opposition or encountered problems.
6) Rerelease beta cards - repeat step 3-6 UNTIL
7) Card/s is accepted by judge (noting that there may always be some opposition) as there are no identified problems AND
8) Card/s is released for use by the public (in tournaments) noting that in the future they may end up back at step one if new problems are encountered.
Steps for Virtual cards OR updating text on useless cards
1) Similar to above
It's just my own feelings on this but the more you involve the community the more success you will have in the long run. Only issue i can see is the amount of feedback may become overwhelming.