Best pro is simply two words - shape shifting
Druid is a very viable DPS class and can tank and heal and with the expansion rez OOC with no 20 min cool down so... why not.
Only looking at the now, as the expansion will bring many new things for all classes (that I care about) I would say Druid is a solid tank, dps and melee or caster and can be a solid healer. It is nice to go into a Raid and be able to pop off OT to backup heal or battle rez the main tank and prevent a wipe (not the preferred method but sometimes it is necessary). Plus flight form ROCKS!!! Being a rogue you can appreciate being able to stealth past the junk mobs to get to the objective. Cat form you can do that... and as a bonus at 68 you get flight form and can fly past them... honestly the 68-70 leveling went faster than about any other leveling (save for maybe 1-10). Instant cast flight form can make quests go very fast and be a life saver.
cons - the biggest now imo is lack of a regular rez for those times when it would come in handy. Having to acquire and carry around 2 or more sets of gear can me tough, but you just get used to it. I can't honestly think of more, I am sure there are some, but I can't think of them.
This is just my opinions - other may feel different. One that I have a rogue at lvl 30 I enjoy playing... though a I reached into the higher levels i played him much less and since I popped 70 I haven't touched an alt.