Batching "admissions" is net more efficient. Plus the whole structure of YC requires it.
We do keep expanding. Every batch has had more startups than the one before. And we're always looking for ways to scale. Just this fall I wrote a bunch of software to keep track of and communicate with all the startups. We'd be lost otherwise, now that the total is up to 80.
I think there are many aspects of the model that can't be scaled via technology. I'm pretty certain that face to face time is really important, and I'm absolutely certain that the casual friendliness of the dinners is vital. Somewhere between the size of a dinner and the size of a Demo Day or party crowd the interactions break down into mingling rather than having actual conversations. I don't know where that size is, but there is definitely a cutoff. The dinner I attended in WFP08 seemed a wee bit too crowded. The noise level was a bit uncomfortable...only towards the end of the evening did I find I was able to carry on a normal conversation at normal levels. I think that makes a very real difference.
Of course, given that I consider the other founders and that intimate dinner experience every week the most valuable part of the program (with pg and Co. being merely the enabler of those gatherings)...one could theoretically split it into two weekly dinner groups (or three, or four, as YC patience and stamina allows), but then you run into the problem of getting good speakers in such abundance. pg would then be running a restaurant rather than a startup starter, though. If a few more good success stories come out of YC, the speaker pool could be bolstered by former YC founder appearances. I enjoyed Sam's talk as much as most (Joe Kraus is still my favorite of the lot).
We do keep expanding. Every batch has had more startups than the one before. And we're always looking for ways to scale. Just this fall I wrote a bunch of software to keep track of and communicate with all the startups. We'd be lost otherwise, now that the total is up to 80.