For mee ther is not enough lines, but only if they care about quality in designs.
An example is the new superheroes line. I really like that designs, and if you mind that TLC give to our magazine minifigs and free sets for testing and reviews, we can check that this new line "accomplish" that top quality.
Moreover, if you think about another "new lines" like LOTR your VISA are crying ^^
On the other hand... Star Wars. It smell like "lack of ideas..."
That's true that UCS star wars have slow down design quality, hope when I see that free set that LEGO set send us for review, I could change my mind.