I think there are two different kinds of people:
Those who have only played a Marauder and think they are great.
Those who have played Marauder AND other classes and know the real deal.
I have a 50 Marauder as my main. Play him constantly. I'm over level 50 in Valor. I have full Champ gear. I run WZes all the time with full guild groups.
It is simply EASIER to play other DPS classes. There is no strain, no stress. You will deal a lot of damage and not have to work hard for it.
Marauders can do a lot of damage...but it requires great gear, and knowledge of the insane amount of abilities they have, and a dedicated healer.
In the Void Star WZ, which is really the only decent method of measuring damage output currently available, I average about 200k total damage reasonably enough in my full champ gear. Ive gotten as high as 280k.
My first WZ on my then Level 11 Operative, I did 175k damage. With 3 combat abilities, I did what takes a great deal of effort to pull off with my marauder. Now compare to Sorcerors. I have to bust my hump to get that 200k...leaping all over, running all over...not dying...while a sorceror stands back channeling lightning AND healing with such ease, and blowing away the total damage we do, with a 100k of healing thrown in...so why play a Marauder in a WZ?
Now throw in Operations. Why would a team want a Marauder over a Sniper? If a Sniper can just sit back in cover and spam buttons, while a Marauder as to run all over the place and constantly reset himself to pour on the damage?
It comes down to this...marauders are already dissapearing from the world because people are catching on as they start playing alts.
I want the Marauder to be awesome. I picked a Marauder as my class simply because I wanted to kick some hindquarters with two light sabers.
But the class is not viable right now. It might be fun to play...but there are better options for DPS...MUCH better options.
Do what I did. Start up an Imperial Agent, get him to 10 for warzones and see what happens in there. The light will click on for you as well.