As far as the "one trick pony" thing...yes, it shows a general breadth of knowledge to wander from genre to genre producing everything under the sun, but it also gives me personally, the feeling that the producer isn't making records of music he likes, just collecting as many paychecks as possible.
I really respect producers like Andy, who make a name for themselves doing the music they love, and can get to the level where they can pick and choose their projects and STILL produce the music they love, instead of just grabbing projects that pay...and making a bigger name for themselves...(ahem Lord-Alge ho's)
Variety is great...but when does it become avarice?