For me that writing process was the most fun. Trying to get an idea to fit in 140 characters and still be grammatically correct is a pleasant challenge. Expanding the character limit may make that easier and therefore less fun - or maybe it'll just give more characters to edit and rearrange.

They gave the statistic that 9% of tweets were at the character limit. That's the wrong statistic though. What they need to check is something like "met or exceeded the limit during composition" because I'd suppose that more tweets are affected by the limit than only 9%. Most of those affected tweets are simply pared down to less than 140 characters.