I don't think this most recent format change is going to increase participation.
I don't want to speak for whole community, but I think that a lot of people disappointed with changes were simply used to the old interface and are not willing to adapt to new one. I've also had some little difficulties with finding myself in it but in the end I find new interface very good. Whole idea of separating lessons from mastering by translations is great - whole process of finishing skill is more diversified and clear in the same time. Providing more information about progress in translating documents and particular sentences is awesome too. Of course some things needs to be improved (I would especially point to selection of sentences for translation according to language level) but I am sure someone is working on it.
There are things I actually like better, the sound seems to work better. The lesson boxes don't bother me at all but not having a couple of translations within the section you are learning doesn't make sense in my mind. Then when I go to the translations section, there's no incentive to even try. Didn't go into this with a closed mind and actually thought it might be better but unfortunately, I'll have to agree with the complaints.
I like the new format! I think it has a nice organization to it - and I like the way the vocabulary is listed in each section. It makes it easier to review the words that aren't as familiar. I would like it if the translations for the words were available with a mouse over the way they are in the main vocabulary section. Edit - I see the translations are available when you access the full vocabulary list for the section.
Luis, I think you've really listened to us and combined the best of both worlds!
I must admit, though, it took me a while to acclimate to the changes. I suggest to those who are still experiencing some disappointment to take some time and learn your way around the new interface. Nothing you loved and appreciated has been removed, you just need to access them differently. For example, many things which were automatic (like doing a few practice sessions before jumping right into the translations) can still be done, just go to the lower right-hand part of the screen and choose "Practice."
Poke around, you'll find your old favorites are still there with a lot more to learn and love!
While I've adapted nicely and moved on... my only comment at this point is it is still disturbing that in order to Master a skill, all the easier translations are completed. That seems a little unfair in my mind, the people who started earlier are getting easier projects. Why not require everyone to translate a complete article? Realize you are working on this and its an ongoing process.
I find it difficult to do a translation in the middle of an article. Granted, I could go back and read all of the sections before, but that feels pretty redundant. Often the selected translations have very little to do with the skill I am working on. In general I think the translations are very helpful to learning the language, but thing the current implementation needs a little re-thinking