Jester David
Hero
Internal playtests miss things. They miss a lot.They have a closed playtest for fine-tuning. Each release for the open playtest has significant overhead; just sifting through all the responses has got to be a major chore. Trying to get information on a million fiddly balance details via open playtest would be next to impossible.
The changes between 3.0 and 3.5 or Classic 4e and Essentials highlight how hard it is to catch all the problems the first time round. Especially when you're designing as you go.
There are lots of middle ground approaches between the small friends and family playtest and the full open beta.
They could move away from the surveys and tap the community, using forums to gather feedback and appointing trusted forum folk to read through and point out important threads or problems that keep coming up.
Or they could keep using the surveys but put the feedback through a tag cloud to check for patterns or anomalies. Or just tap interns to skim the documents.
They could expand the friends and family playtest, opening it up a little more.
Regardless, one of the stated goals of the edition was to unite the fanbase and make a game that has multiple playstyles. But the playtest focused on an old school/ Basic D&D type game. While WotC seems happy with the results of that, they've done nothing to attract modern gamers, and have only pushed away 4e fans.
If we don't see a playtest of the modules then many fans might just spend the next year finding new games and forgetting about D&D or WotC might release a tactical module that doesn't satisfy the needs or playstyle of that community.