It very much depends very much on genre where the balance of emphasis lies in terms of what is typical for each genre regarding the feel and the nature of the song. For example some genres are dominated by depth of lyrical meaning or the story of the lyrics, while others still are predominantly rhythmically or melodically dominated. But all components of the song have to work well together to create that whole working song, no matter the complexity of the piece.
The style of lyrics, their content an language may vary, but they need to be appropriate... just like the music. Even if the lyrics themselves turn out to be vocal sounds to add shape and rhythm and heighten emotional response (be-bop-alulla). Some genres require certain language and colloquialisms, or a depth of meaning. Above all, simple or complex, they have to work within the context of song and genre.
How seriously you take the lyrics? I guess it should be as seriously as you take the music itself. As seriously as you take songwriting. Afterall, songwriting is a craft that songwriters take seriously because they want the song as a whole to be as good as it possibly can be. If the writer has pride in their work, they care how listeners think and feel in response to the song and no matter what else they want it to shine as a complete piece fulfillng whatever role they have planned for it.
How seriously you take writing depends also on ambition and your work ethic. Some writers are careless by nature or even treat their listeners with contempt believing all that matters is that they get to express whatever they want without caring about the listeners opinions, or they are lazy and contemptious, or arrogant.
So it literally comes down to the individual, their motivation regarding songwriting, the respect they have for their audience and themselves as a songwriter... and perhaps the importance of what they are communicating.
Of course, self respect comes into it too. If our songs are important to us, then we approach them seriously no matter the genre, no matter the complexity or the emotion of the piece, no matter the song component. Every part of the song fills a role in making the whole.
In other words don't equate the dominance or balance of elements to feel, or possible success of a song with how seriously you should approach any element of a song. If you care about the quality of your songs then you take it all seriously. Every song represents you and what you stand for or perceive or believe to your audience and the rest of the world. This is true for all levels of song writers, professional or not. If you care about your reputation, then you care about what you produce. Simple as that.
Can easy to write songs be successful? Sure. Can songs with crap lyrics be successful? Sure... but in the long term generally less so than songs with better more thought out lyrics. A draft lyric can take moments or months to write, the important thing is.... do they truly work and work well? Do they contribute positively to the song? Are you willing to accept "close enough"?
Just dont kid yourself that lyrics are unimportant. They fulfill a huge role.
Dont kid yourself that quality should be forsaken for speed of writing or to increase the number of songs in your portfolio. I say that because it is something I have seen many writers mistakenly do.
Listeners expect songs of a quality, and they can label artists and writers very quickly. Perception and expectation await your songs and first impressions are hugely important to listeners. They can dismiss your song quickly labelling you everything from "turn it up" to "turn it down/off". They can see you as an amateur or a pro, and as most are likely independents, they start off with an expectation of lower quality. Be the one that bucks the trend... deliver only the good stuff.
Writing a hit is pretty well down to the scale of the marketing, and having a song that fulfills the hype. So, knowing that listeners will get to know your lyrics, and good appropriate lyrics are a prerequisite for longevity and depth of success... why would I not want my lyrics to help rather than hinder the song and it's hopefully successful promotion campaign? Why take the risk? It would be a bit like forgetting to put petrol in your car and hoping you can go the required distance. Why make it an issue? Just fill the tank and at least remove that from the possible reasons for not getting there! Easy
