Sorry, I didnt mean that we should stipulate what lists had to be used, I only meant to suggest that if those who felt inclined played a fairly rigid themed list before and after, it might help us get to grips with which themes will work with the new codex, and which themes we have generally abandoned since 6th will be viable. I didnt mean we should do anything the codex didnt permit, quite the opposite -I would want to run lists that are likely to still be possible in the updated codex.
For example, I know that a biker list is strong, particularly with biker nobz, if a little unforgiving if not played carefully - be nice to compare with a similar game after the new dex to see if the same is true. Similarly, not many people use stormboyz right now, but I'd be happy to run a list with them in so that I can run the same thing after and see what has changed. Examples go on, and it may be that many people don't need reminding what's good or bad about the current options; for me personally the contrast would be interesting.
Most people favour one or two lists, be it kan wall, speed freaks, green tide, etc. And they tend to favour them even if they aren't very playable in the current incarnation, and want to know if they're any good again when something changes. But of course it doesn't need to be set by the campaign; I just thought it mightigive an additional purpose to the exercise to run the same lists (as much as possible) before and after, and compare - whether that's for individual units or army themes.