26% crit (+5% from moonkin) (this is 16% lower than shaman due to shaman talents)
Base = (1883+2187)/2 = 2035
Base w/ hot = 2442
2442 + .810 * 2100 = 4143 (.81 coefficient from the druid WotLK preview thread first post)
4143 * (1 + (.95 * .31)) = 5363 (1.5 * .3 = .45, so 195% crits, like shaman)
base cast time = 1.5 / 1.15 = 1.3
avg cast time = 1.3 - (.5 * .31) = 1.145
5363 / 1.145 = 4683 hps
mana cost = 3796 * .18 * .9 = 615 mana
5363/615 = 8.72 hpm
So I'm showing the average LHW (inc crit) at 6622 for 5044 hps and 15.84 hpm. I guess it'd depend on your definition of 'consideraby', but 250 hps is a decent margin. If the druid isn't stacking crit, I'd guess the margin would be wider (but I'm too lazy to theorycraft it since I didn't build a spreadsheet).
As for the totem of the third wind, it's definitely the choice for this style, as mentioned in the OP. I did a heroic with an ele shaman and was surprised at how much SP ToW provides. Managed to get up to 2318 SP with a feast food buff from another member of the party. 2400 SP LHWs (I use the old nagrand LHW totem) and a 3k earth shield on a geared tank are ridiculously overpowered for strat and violet hold. Add a mixology frost wyrm flask and an s5 totem, 2700 SP LHWs appear to be within easy reach. With 2t7 and my current crit rate, LHW would be just over 20 HPM on a glyphed target, which seems...high.
Is this ~15% more HPS over glyphed LHW including TW? Seems like the max HPS combo you listed (RT->HW->HW->CH->HW->HW) would output much more than +15% HPS over glyphed LHW spam.
I'd love to be able to skip Healing Way, but the other Resto Shaman I raid with (10 man) insists we'll need it on fights like Patchwerk.
The 15% HPS is NOT including TW. You can check my spreadsheet (which reflects my stats but...), but those HWs are at about 7k hps versus 5k hps for LHW spam. With healing way stacked, those go to 9k HPS. The problem with both those HW numbers is that they do not take overheal into account, which will cut both the direct HPS and well into the AA numbers. While I tend to not get a lot of overheal on LHW crits, I get enormous overheal on HW crits unless they're the emergency NS+Tidal Force variety.
As for needing it on patchwerk, I didn't need to go beyond LHW spam while taking care of the hateful tank in naxx 10 on our first (and very slow at 5:45) kill by myself. We've been running 3 healers (me, holy priest, Holy Shock/JotW pally for replenishement) for safety since we're learning the fights and I've taken to being the switch healer on subsequent attempts and try to keep Ancestral Fortitude+Riptide up on both tanks. It _may_ be necessary to drop into HW cycles if you're trying to solo heal the MT below 20% but I haven't had to try. No clue about Naxx 25, we don't have 25 80s yet.