Below are my thoughts on the 2 scenario's you outlined.
1. Power Words
There will ALWAYS be a few top power words that people pay more for than other words, even if the power word doesn't fit the extension, the value will be higher than other words. For example, the following are power words that have a long history of HIGH ppc, HIGH competition, and Key player investors: Casino, Attorney, Gambling, Porn, Medical, etc.. Even if you couple one of those words with an obscure gtld like: Casino.Estate, Attorney.Music, Gambling.Kitchen, Porn.Dog, Etc.. Those Power words will still be worth 10x more than other dictionary words. We see it every day, so my opinion is that it will remain the same even in the new gtld's.
2. Generic Key Phrase Hacks:
Unlike generic keyword hacks (e.g. camp.us / butterf.ly / etc.) that mainly have collectors / novelty value. Key Phrase hacks (e.g. Real.Estate / Fast.Cars / Cheap.Food / etc.) are going to change the game for individuals and companies looking to manipulate search positioning and compete head on with top ranking .com counterparts. We already see cases where a key phrase .info / .org / .net / etc. sit higher in the search index than the same key phrased .com, so it's really not a new strategy. It will however provide a little more direct saturation, enough to knock the blocks out from under those that got to comfortable with their past achievements.
Granted, there's lots of factors at play besides just using keywords in a domain, which is a debate in itself as to how much value a domain with keywords actually gets. Each search engine (Google, Bing/Yahoo, etc.) used their own specialized algorithm to value a website and determine where it should be placed in the results index. So, just to clarify I'm NOT saying keywords in a domain is enough to compete, just saying that it's one of many factors and a visual motivator to jump in the race with the intention of competing.
3. In Conclusion:
I think there will be an ample amount of bold claims of "The next big thing" or "This is the best new gtld". Like with gtld's and cctld's of the past, it's all to common to see the head to head heated debates about how one is better than another (E.g. .tv is better than .us / .org is better than .info / etc.). And each side of the debate comes out with a few key pointers to support their stance. Both sides have some valid reasoning mixed in with lots of hype, speculation, day dreaming, and investment risks based on blind faith. It's hard to nail down a definitive investment path this early in the game, however I do believe that there will be the same kind of forked road trend, where several small hyped up strategies get promoted in a "worked for me, it can work for you too" type scenario.
Just my opinions amongst millions of others.
Eric Lyon