Having recently read about a slightly different way of doing sealed, and having some ROE packs laying around, I thought I'd give it a go with a friend of mine after a lecture yesterday. The two main differences between the mini-sealed and normal sealed is that mini-sealed uses 4 packs instead of 5 or 6, and has a minimum deck size of 30 instead of the usual 40. OK, I think they're both the differences. I think the rational behind the 30 card limit is that constructed decks are 60 card minimum, and 30 is half that. I can't seem to find the article I read about it, but Paul (who I did the mini-sealed with) knew what I was talking about so at least I didn't completely dream it up.
We first opened four packs for my pool to have a look at and think how possible it would be to build something with a much more limited selection. Green was the stronger colour, with Red coming second, and Black having a few splash-able cards. I ended up putting together a deck with some big stuff at the top end (two eldrazi and the wurm), although didn't really have much in the way of mana fixing/acceleration (two or three token generators and the 3 mind stones taped together). Paul's deck was mainly blue and green (with about half the green cards fixing mana, allowing him to splash red, and I think black).
We played a game or two, and everything seemed to be just like a normal limited game. Then we realised we had build 40 card decks (out of habit) instead of 30! It was reassuring to know that even with the lower number of boosters, it was possible to build a normal limited deck, even with an even more limited card pool. We changed the decks around a bit; I took out Black as I only had a few cards, but left in some of the other higher costing spells. Paul took out green, and splashed Red and Black; with the smaller deck size, splashing would be a bit easier (in theory), plus he did have a bit of fixing and card draw (which gets even better with small decks).
Most the games we played with me having the higher costed stuff didn't go too well for me, usually being one or two off casting a big eldrazi (the 8 cost one, so it was possible) or something, and the format seemed quite fast, especially with Paul's small blue levelers and fliers. I changed by deck around a bit again, taking out the eldrazi and triple mind stone, but leaving the wurm as the highest costing card. With some more lower costing spells, I did a bit better and was able to win a game or two.
All in all, it seemed like an interesting format; fun and possible to make a deck without having to stretch your card pool too thinly. Whether it will become and actual format or not I don't know, but my initial experience with it was a fairly positive. It will probably take some time to try and figure out how to optimize deck building properly (mana base/curve etc.), but even through some initial decks and games it seems like a viable format.