The time between expansions is a great opportunity to change your play style. You can become more proficient with PvP, learn to not stand in fire, or pick up a new class. It can be hard to find guilds to take you in as an undergeared, fresh class player, but things are also a lot more forgiving. You'll be under geared but with everyone else around you rocking some of the best gear in the game, you don't really have to worry about your gear being too huge of an issue.
For me, this is also a great time to switch between overall play styles. Back in Burning Crusade I was a hardcore raider. 25 hours a week of raiding, our guild made it into the top 150 in the world, and I'd tank like an army drill sergeant. When Wrath came around I floundered and had enough, I went down to being "mid core" -- the gray area between casual and hardcore. I'd raid with dedicated groups, but I wouldn't do more than 10 hours a week.