Those things worked like a charm. They weren't flexible tho, and functionality could be offset to keyboards connected to USB
The current headphone jack is thick (leaving less room for other stuff in phones), it collects dust and is basically a hole.
These are design problems, they'd have to be solved (because that's what makes the 2,5 mm stupid: it ADDS problems).
I'm not sure what they're planning, but i agree on one thing: there's a lot of stuff (high end headphones for example) that would stop being useful if the connector would change alltogether.
That said, improving it, improving everything, should be and is a focus point in (imho) ANY good business.