Not enough people are advocating for Elemental Warding, the 6% damage reduction talent in Elemental tree. So to put my two cents: every decently geared Elemental Shaman should have this talent if they want to do end-game raiding. But it's not a good investment for 5-man heroics or leveling.
In a proper raid setup, you can or drop points from Convection, drop Unrelenting Storm entirely, or put one point in it and drop Shamanistic Focus. You're never going to have mana issues unless you're doing something really screwy.
The possible (bad) reasons you have mana issues in Ulduar:
1) You've died and ankh'd
2) You're spamming chain lightning
3) You're spamming shocks*
4) Your raid has no replenish
5) You aren't using TS when it's off CD
6) You aren't refreshing WS when it's down
* If you really need to spam shocks on some fight, just pick up SF with the extra point; problem solved.
If you're doing 1, then don't. If you're doing 2, 3 or 4, then there's probably something wrong with you or your raid setup. And if you can't find time to remedy 5 or 6, you need to learn to hot key WS/TS and use them while running.
There are very few fights (any?) in Ulduar that are 100% stationary but require mana regeneration. There is at least one stationary fight where mana regen is meaningless. The majority of the fights require mobility, which is when you should take advantage of your free mana from thunderstorm and water shield.
You get about 150 mp5 from Unrelenting Storm, but get the same amount from consistently using Thunder Storm when it's off cooldown. You won't get more than 50 mp5 from using Shamanistic Focus in a normal rotation. A decently geared Shaman will not need these talents unless they are in exceptional circumstances or doing something wrong.
The 6% damage reduction is like a mini-defensive stance, and is basically free with your talents as long as you aren't having mana problems. Your healers may not notice, but if everyone in the raid had talents like this, it would be an obvious boon. Unless your gear sucks or you can't manage your abilities correctly, consider putting 3 points into it.