Rshams are always limited by the following:
-Cant do much of anything while CCd (Weak HoTs, no major CDs usable while in CC)
-Very reliant on casts
-Very unreliable and non-spammable CC (Hex gets dispelled, has to be cast, cap totem killable and also arm time)
I think they are the most balanced healer by far. Not that Rdruids are OP, they just synergize way too well with mages and SotF is like NS clone every time its up.
You must not have played during Catalysm.