There are times carrying is needed, and other times it is not. If your a tank being healed by a decently geared healer while your wearing PVP gear and PVE DPS gear as your tank set, chances are the group isn't going to want to carry you after the fourth pull. Similarly if your wearing lots of gear with hit as a healer, a tank is going to oust you (at least both situations are things I do as heals/tank). If your in an important roll, you need to gear right and be expecting not to be carried. Those who only DPS will never fully understand the concept of pulling your own weight and making the right choices in your gearing and such in PUG environments (this comes from a person who pugged 7/12 ICC back in the days as a lock).

All in all my advise to everyone is to do research on any class/role you intend to partake in for the raid finder, make sure your items are for the correct environment (as in your wearing full PVE or less than 3 pieces of PVP), come with your gear enchanted/gemmed/reforged (when applicable as not all items have to be reforged or they can't be in some cases) so that you can bring your A-game to every encounter performance-wise. After that, simply read up on the encounter, be prepared to shell out on repairs from the 20+ wipes you are about to receive, and be happy you get to enjoy something that was typically very hard to accomplish in older content.