A look ahead -- More Hard-Forks in Ethereum's Future?

I have been following Ethereum with interest since its announcement. I started learning solidity recently and have mocked up a DAO framework or two. However, Today I Learned™ that Ethereum's POW phase is scheduled to kick-in soon-ish: a helpful stackExchange article estimates:

Blocktime over one day in July 2017
Difficulty on 2017-08-02 is 219.9 P and average blocktime is 26.06 hours.
Difficulty on 2017-09-05 is 879.6 P and average blocktime is 4.342 days.
Blocktime over one week in September 2017
Difficulty on 2017-10-02 is 2.639 E and average blocktime is 13.02 days.
Blocktime over one month in October 2017
Difficulty on 2017-11-05 is 10.55 E and average blocktime is 7.443 weeks.
Difficulty on 2017-12-01 is 28.14 E and average blocktime is 4.962 month.
Difficulty on 2018-01-05 is 112.5 E and average blocktime is 19.84 month.

I heard that the so called "Ice Age" is going to be delayed.

I have seen sources that say a HF is necessary for such a change. Is that true?
It would be interesting to see the dynamics of a currency that proceeds ahead with POS in lieu of such a hardfork.

Discuss.... :-)