Usually my groups go smoothly. Here's the latest log (on a Thursday night) from my alt, Mistanny:
http://www.warcraftlogs.com/reports/XQ9cb6NBFrWD71kd Sure, I'm able to get into flex, and have just started Normals, but there are a few trinkets I can use from LFR still (2 from first wing, 1 from each of the others). If a friend needs LFR, or if I'm helping out a nervous newbie tank, I go with them. I queued this time with one of the tanks and a DPS friend who needed the valor and also still has a couple upgrades from it.
Abysal, if the group hits enrage with a couple of people dead, but wouldn't have if DPS was a hair higher, then DPS is still an issue. Likewise, having better DPS (specifically people who actually switch targets rather than padding) is important. It particularly makes a huge difference in Garrosh (fewer empowered whirling corruptions, handling the sha adds and MC's better), Galakras, Naz, and Immerseus. It also applies to Noroushen, but in LFR, the cleanse targets are chosen randomly. People can still get better numbers by focusing adds until they go in.
Normie, a lot of people apparently care about Grimreaper's alt's damage. Otherwise, there wouldn't be so many requests for logs.
Grim, I'd offer to let you come along with me and my friends for LFR/Flex, but I don't think we can group since you're EU and I'm US.
I hope you can find some tank/healer friends and/or guildies to go with, and do check out the newbie groups on OpenRaid. I know you aren't a newbie, just that those groups are willing to take low ilevel toons.
Prairie, Grim mentioned that himself more than once.
Theholypally, did you mention it to them? I usually use my transmog as a visual cue to help remind me if I'm in the wrong set, but I've accidentally tanked in my holy set/tree set/boomy set before, and vice-versa.