Not even in one of the "Blues" areas(50-55), at those low levels every 2 levels or so get you a new goodie, a new toy to play with, and talents are still given you gravy. Here is a list of some exciting stuff for different classes in the mid 20's to 40
Druid: Well you just got angry sea lion form, and even more recently cat form; you are always getting new toys to make being a druid more fun (read more DPS)
Dash is at level 26, and that’s kind of a game changer, level 30 gets a channeled AoE heal!!!!, and travel form(move faster than your buddies with this free preview of a mount.
Hunter: 24 just got you Beast lore, it is fun sometimes to just see the info on animals so that you can think of what you want in future pets. At 26 you have rapid fire a super fun skill that will take you a few levels to figure out that you want to be using it a lot. Level 30 brings you Feign Death, the ultimate PvE tool, at the same time you also get flare, the rogue finder, how fun is that?
Mage: this is one of the biguns, as a mage you just got counterspell, and life is not much more fun that counterspell, you can spend almost 2-3 levels mastering the perfect time to use it. 26 is when AoE madness starts, frost spec mages can Start to do AoE farming with dang good efficiency, and 28 is the start of manna gems, this is a amazing time to be a mage.
Pally, Sheesh, don’t ask me, Mine made it to 45 and I stopped playing him, it was work to get him to 45(as a side note the toon was not soooo bad, and I would even think of making a blood knight, the issue I had was Pally overpopulation)
Priest: One of the low points in a priest life is the mid 20's, well some classes got this time as a super fun time, it is a lil harder for the priest, at 25 the last "New" spell you got was Mind vision. There are some new tricks waiting at 30 and a few race spells but as a priest you are always wanted for instance runs, that is if you want to heal, so I have never been in the 20's for long as a priest, simply being a priest gets you "Want to do BFD?" say ya a few times get your loot and be almost to level 30 and on your way to a mount.
Rogue: not my bag, I really don’t know.
Shaman: These guys are always getting new tricks(or totems), level 24 just got new stronger versions of previous spells, but 26 holds some new guys that are totally fun, but the super gravy hits at 28- 30 Water Walking, recall(15 min cool down hearthstone) and your last totem, no dragging backside for a shaman.
Warrior: like Rogue, not my thing.
Warlock: ooooooo yea, every level as a lock is fun, but mid 20's and up are a good time to be lockie. 24 gave you some tools, but nothing amazing, but level 26, buwhahahaha you can now use your succy to seduduce folks, extra CC is good.Curse of Tongues is a fun one on PvP servers, 28 holds banish and now you are boss of elemental killing, if they give you issues, banish , bandaid and keep going. level 30 gets you a fel pup, hellfire and a spell you can have fun with for a long long time, Enslave Demon.
I hope you find what you are looking for in rogue if not, go back and try one of your old toons, you may just find some aspect that was eluding you before.