To go back to the core question of this thread, I personally don't believe that Lin Sivvi or Rising Waters will be banned. There won't be anything resembling a Rebel in the entire Invasion block, because WOTC R&D sepcifically said that from now on, they'll avoid mechanics that require you to shuffle your deck every turn (wastes a lot of tourney time). The only color that has a really tough time handling Lin Sivvi is red, and if I know Mr. Garfield and his previous influence in Tempest, red's gonna have a field day in Invasion. Maybe there will be a new burn-type instant or sorcery that removes destroyed creatures from the game, like Disintegrate.
Rising Waters is simply an overcosted blue Winter Orb. It's overcosted because it's blue (this is one color that most people agree should be kept slow), and because it's an enchantment, making it less vulnerable than the artifact Orb. It slows games down, but that's what blue control is all about. Besides, it is no more overpowered than Replenish is, and you don't see the banning of that ever being an issue, do you?
Now, the Rishadan Port is another issue. The theme of Invasion is to bring back the multi-colored decks. A lot of people want that to happen. If they find out that Port interferes with this intention too much, then they will ban it. If they make the set such that the Port is no longer as dominant, then they won't ban it. If you look at the rumors, they all say that Invasion will have cards that can handle Port. For example, one of the most prevalent rumors is that they're reprinting Wasteland.
They won't make the environment any slower than it actually is. The new mechanic can only make decks more versatile, though not up to the speed we were used to back in the days of Tempest. If anything, the up and coming Type 2 will certainly be much more interesting than the last. We won't have to deal with decks based mostly on rares anymore (Tinker anyone?).
To be honest though, I'm not really affected too much by this set cycling thing. I rarely play in tournaments, and I never use Type 2 for my casual decks. Too limiting for a casual player, you know.