We did the 'new' tour in August and although we hadn't done the old one to compare with, we really enjoyed it. Ours was as described above, but the advantage we had was that we were the only 3 people on the tour! (me, DH and DD5). So our daughter got 1:1 attention the whole time from her own CM (who we then bumped into a couple of times later in the week, then we had to go and visit her on our last day), she got to work out all the clues herself, find all the treasure boxes herself and at the end, she sat and showed Mickey the puzzle she'd put together to find him - I'm sure that made a big difference, 18 does sound like it would have been a very big group (even with 2 CMs).
So for us, yes it was definitely worth the money, our DD talks about it a lot. It would have been really nice to have met more characters, but since we didn't know that used to happen we didn't miss it!