Wyll flirting with Lae'zel gives just as much insight into the two of the characters personalities as Gale and Lae'zel conversing with one another. One shows that Lae'zel doesn't understand the concept of romance/love(something she eventually comes to find she actually enjoys when you romance her yourself at the end of her Act 3 scene) and that Wyll is a romantic by nature. Just because he strikes out doesn't mean those conversations aren't substantial to either characters. Or well, it use to be, they've removed it since then which is a shame, because it was funny moment between the two, but I guess a lot of people complained about it in feedback.
The topic was chill, not substantial. While Wyll's banter with Lae'zel and the other characters does certainly give insight into him and the others, I find most of his comments needlessly offensive, much more than those of the other companions. So I was wondering if this was a matter of party combination or personal perception. At the very least he seems to have chronic foot-in-mouth disease - but that might be personal perception.