I don't know about you, but my lowest wild growth ticks are at 2,3k unbuffed, while rejuvenation ticks for roughly 11,5k
If I assume your ticks are correct without checking them up I end up having:
2*4*6 = roughly 50k healing from Wild Growth.
11.5*3 = 35k healing from rejuvenation.

Do keep in mind that the average tick of wild Growth is larger then 2k,

The numbers are very rough, but in any kind of raiding gear your numbers should be higher if you're pressing wild growth then rejuvenation after swiftmend.

Rejuvenation scales less with spellpower as well, roughly 15%, this means that the longer into the expansion we get, the larger the impact is of using Rejuvenation rather then Wild Growth.

Edit: I totaly missread wowheads spell tooltip that has different coefficency on rejuvenation and wild growth, total of WG and per tick on Reju, therefor it might be ticking more in a raid enviroment, here are the numers from my world of logs from last sunday.

Rejuvenation average tick:
12339

WG Average tick:
2402

Doing the napkin math again we get the following:
12339*3 = 37017 for rejuvenation
2402*4*6= 57648 for wild growth, so it'll be quite a while untill the spellpower is high enough to cover up 20k healing per activation of the spell.

This is a bug with insane amounts of haste, it doesn't only affect WG, but it's normally the only spell we notice it on. It ticks for the average value instead of decreasing so it's not game breaking.

The problem with that is that you have to delay your rejuvention cast by up to half a second, that half a second adds up really fast when it comes to healing done, using rejuvention + swiftmend as fast as possible means you won't be able to swiftmend when the CD is over so you need two rejuventions per "good" rejuvention, if you're not using unglyphed regrowth which is quite poor when it comes to tank healing.

Estimating the value that 50% haste adds to one cast of a DoT doesn't need to get too fancy--just increase the total healing from the cast of the DoT by 50%. This will be accurate within one tick, depending on where your haste was relative to breakpoints in the first place. (In practice, we will probably get slightly under 50% added ticks on average, due to the bias towards gearing to just after a breakpoint).

A Rejuv cast does substantially less total healing than on WG cast. So it's the desired SotF spell when you're not using WG, but still much less benefit (incidentally, if you were worried about rolling a hasted HoT on the tank, you'd just SotF your Lifebloom).

I've not tried SotF much, but based on my experiences playing Resto a lot so far, I'm understanding less and less why it would be appealing to me. I will try it some more soon just to see if this changes anything (admittedly I have an issue with not using cooldowns like Tree often enough in the first place, reducing their value).

-------------------

Unglyphed Regrowth. With 60% crit and 5% from raid buff, you must be gearing somewhat heavily for crit to be reaching 80%. Now certainly you can do this, unglyph Regrowth, and have a pretty strong spell. But you can also bias your stats into heavy mastery, keep Regrowth glyphed, and have both benefits (as well as a better benefit to your other spells from mastery rather than crit). So it seems the most efficient min/maxing is to make crit a dump stat, cancel out the detriment to RG using a glyph, and get a better value by putting all those stat points somewhere else.

The problem with that is the fact that you have to spend atleast a GCD, I haven't looked into it yet, but DoC is in general good for feral because they are not limited by GCD's, rather by resources, a resto druid in general is limited by GCD when the healing is needed. There might be ocassions where 30% healing on one spell can outshine an entire extra spell, but I'd assume that is very rare and needs alot of preparation.

Edit: After reading the tooltip it's even less worth, you can't procc it with moonfire only (while running) so therefore you have to cast a wrath, which is about 1.9 seconds for me (Not counting the other things that affects spell casting like ping). It just seems so much of a waste for simply 30% healing.