This is big.
Huge.
Fashion history is writing itself right now.

What is happening? Burberry and Tom Ford are going against the current unsustainable fashion cycle by reformatting their their shows to twice a year. February and September, their clothes will be seasonally relevant THEN, and more importantly, clothes and campaigns will be ready to buy/launched the second the fashion show ends.

HISTORICALLY, 

fashion shows were never intended for the consumer. A fashion show was a preview of what the designers had in the pipeline, so press, investors and wholesale buyers could speculate and place their orders on the clothes 6 months in advance of clothes hitting the racks.

This is why the Spring Summer shows are in September, and the Autumn Winter shows are in February.

The fashion industry is founded around this 6 month delay; from Zara to Fashion publications, this is how the industry works.

However as we have all come to know; this isn't how the system works anymore. Fashion shows have become spectacles; for we are a Society of Spectacles (Debord, 1967). We millennials are driven more and more by the Experience Economy (Pine, Gilmore 1999). Growing up with recessions and less confidence with money security: it has been argued our whole generation puts more weight on experiences now, than consumer goods. (Pine, Gilmore 1999)

I would argue that fashion shows are now our business. We no longer sit back and wait for the press to report on the shows and be fed second hand: we live stream the shows, line up for hours outside; even exploit the positions of power we are in to consume fashion shows, just as we would consume the products 4 months later.

We also need to take into consideration the instant gratification demanded by us millennials. If I see clothes or a trend? I want it now. I am not going to wait 6 months for it to come out.
This is what brands such as Zara, who have a 6 WEEK turnaround (they see 70's trend, it's in stores in stores within 6 weeks from the trends conception) exploit.

EXAMPLE: I am not going to be able to buy Tom Fords' flared jeans for 6 weeks, so I am going to go to Zara in the meantime. But often before the trends even hit the designers racks: the trend has moved on.
Zara: makes the profit on Tom Fords trend, Tom Ford: misses the boat.

What has changed? 

Fashion shows are no longer for wholesale buyers, investors or press: they are a publicity stunt for the consumer. A shopping experience.

Whether that be experiencing the fashion shows on the frow (front row), via snapchat (as Burberry has done), or through a music video (see Tom Fords' new collection and Lady Gaga's new song in this music video) the consumers expect the fashion shows, just as naturally, we expect the clothes as soon as we see them.

Pros and Cons 

of this new implication to the greater fashion industry.

Pros

Less Pressure on Designers
If you read my article on why Raf Simons was leaving Dior, the reason was that the model of the current fashion cycle (some designers produce up to 14 capsule/full collections a year) places an unsustainable pressure on designers.

Gender Blurring/Neutrality
Which is an issue very relevant today; is once again, unsupported by the current fashion cycle.
Having mens fashion week and women's fashion week at the same time, will allow for the possibility at least, of a gender neutral collection, or clothes being presented as clothes, on gender neutral models. Something integral to this generations cause.

Burberry SS16 Show. Source: fashiontimes.com

Easier for all those involved in the Fashion industry
One Burberry runway for both men and womens show.
One fashion week for industry specialist who have to report on both mens and women's.
Opportunity for those who have only visited mens week or women's week to expand/explore.
The chance for there to be a greater PR cacophony for a brand with a one show hit wonder (imagine twitter hashtags as #BurberryShow as opposed to #BurberryMenswearShow and a few weeks later #BurberryWomenswearShow).
LIFE WILL BE EASIER.

Brands will get to financially benefit from their trends 
(as was always intended) Sorry Zara.

All brands will have to follow suit
and I'm talking, everyone. Burberry and Tom Ford are colossal brands. As I said, this is huge.
It's like dominoes. If they have? Everyone is going to scrap the dated fashion calendar.

Cons

Highstreet brands with 6 week turnovers
...will be forced to step up their game. No more riding on the coat tails of others. That gap in the market will be saturated. However that being said; Zara's high fashion designs and high street prices will surly remain unrivalled.

Fashion Publications
Will be having kittens. They will have to step out of their time machines, and create magazines 6 months in advance MINUS the foresight of trends. (Maybe consider making them 3 months in advance now? Just an idea!)

All brands are going to follow suit
Not everyone is going to like it. Restructuring a brand isn't free or easy. Plus it's a major edge lost for the brands that benefited from 6 months ahead foresight.

PR's and Celebrity Stylists
are too, going to have kittens. How on earth are they going to dazzle and wow celebrities with the latest seen-but-never-worn hot off the catwalk trends and looks, if the general public already has access to it? *yawn, boring!*
'Without envy, glamour cannot exist' -John Berger
Does this mean celebrities will not have to be offered bespoke everything by the brands? Who knows how they are going to make up for this loss!

Conclusion

Not much more can be said? It's time for us now, to sit tight and watch this all play out.
It is certainly a better system than that previous, but how well is that going to work for smaller brands? Publications? High street brands? This is going to have ricochet effects from the major fashion houses to bloggers; just you wait.