Firstly, you may know this, but I'd be careful about switching to Regrowth from Nourish. It's probably fine if you are casting each successive Regrowth on a different person, but Regrowth spam on a single target isn't really a good idea at 80. The majority of healing done by regrowth is from the HoT, not the initial heal. You won't get the same single-target HPS spamming Regrowth as with Nourish spam.
As for what to do about the softcap, you do have a couple options. Like you mentioned, removing the points from Nature's Grace isn't a bad idea. Filling out Revitalize and then Tranquil Spirit could be points well spent. Even Improved Tranquility could be a good choice if you are mainly healing heriocs.
Re-gearing isn't bad either, if it's worth it for you. Haste is one of those stats that's become better and better for Trees recently. There are those who will even go as far as gemming haste over spellpower. It's going to depend mostly on which spells you use to heal. My guess is that even with a small amount of haste wasted you likely aren't to the point where dropping haste for another stat is preferable.
Crit is nice if you have the 4t9, and if you are pulling something like 900ish - 1,100ish haste. This would get RJ/WG and a non-NG Nourish down to under a second. You might find haste hard to replace until this point.
Also, in 5 & 10-man content the drawbacks of the Rapid RJ Glyph aren't felt as heavily. I can't say with certainty, but I'm guessing the number of people you can keep RJ on is still limited by the group-size and not the duration of the HoT. If this is the case you will be getting an added benefit from haste there, making the stat even harder to swap for.
The best thing might be to look at a couple of spreadsheets if you have the inclination:
linky linky The first one is a bit outdated, and I don't know if the patch 3.3 GotEM changes have been implemented yet. The second is up to date, but I don't recall it being able to handle different healing rotations very well. So you may have to use both to get the numbers you are looking for.
Edited, Dec 18th 2009 9:22am by someproteinguy